diff --git a/src/main/java/com/metaweb/gridworks/model/changes/DataExtensionChange.java b/src/main/java/com/metaweb/gridworks/model/changes/DataExtensionChange.java
index 19547445d..fbf4304b1 100644
--- a/src/main/java/com/metaweb/gridworks/model/changes/DataExtensionChange.java
+++ b/src/main/java/com/metaweb/gridworks/model/changes/DataExtensionChange.java
@@ -19,14 +19,21 @@ import com.metaweb.gridworks.model.Column;
 import com.metaweb.gridworks.model.Project;
 import com.metaweb.gridworks.model.Recon;
 import com.metaweb.gridworks.model.ReconCandidate;
+import com.metaweb.gridworks.model.ReconStats;
 import com.metaweb.gridworks.model.Row;
 import com.metaweb.gridworks.model.Recon.Judgment;
+import com.metaweb.gridworks.model.recon.DataExtensionReconConfig;
+import com.metaweb.gridworks.protograph.FreebaseType;
+import com.metaweb.gridworks.util.ParsingUtilities;
 import com.metaweb.gridworks.util.FreebaseDataExtensionJob.DataExtension;
 
 public class DataExtensionChange implements Change {
 	final protected String				_baseColumnName;
 	final protected int		  			_columnInsertIndex;
+	
 	final protected List<String>        _columnNames;
+	final protected List<FreebaseType>  _columnTypes;
+	
     final protected List<Integer> 		_rowIndices;
     final protected List<DataExtension> _dataExtensions;
     
@@ -38,20 +45,27 @@ public class DataExtensionChange implements Change {
 		String baseColumnName, 
 		int columnInsertIndex, 
 		List<String> columnNames,
+		List<FreebaseType> columnTypes,
 		List<Integer> rowIndices,
 		List<DataExtension> dataExtensions
 	) {
     	_baseColumnName = baseColumnName;
     	_columnInsertIndex = columnInsertIndex;
+    	
     	_columnNames = columnNames;
+    	_columnTypes = columnTypes;
+    	
         _rowIndices = rowIndices;
         _dataExtensions = dataExtensions;
     }
 
     protected DataExtensionChange(
 		String 				baseColumnName, 
-		int 				columnInsertIndex, 
+		int 				columnInsertIndex,
+		
 		List<String> 		columnNames,
+        List<FreebaseType> columnTypes,
+        
 		List<Integer> 		rowIndices,
 		List<DataExtension> dataExtensions,
 		int 				firstNewCellIndex,
@@ -60,7 +74,10 @@ public class DataExtensionChange implements Change {
 	) {
     	_baseColumnName = baseColumnName;
     	_columnInsertIndex = columnInsertIndex;
+    	
     	_columnNames = columnNames;
+        _columnTypes = columnTypes;
+        
         _rowIndices = rowIndices;
         _dataExtensions = dataExtensions;
         
@@ -140,9 +157,12 @@ public class DataExtensionChange implements Change {
             
             for (int i = 0; i < _columnNames.size(); i++) {
             	String name = _columnNames.get(i);
+            	int cellIndex = _firstNewCellIndex + i;
+            	
+            	Column column = new Column(cellIndex, name);
+            	column.setReconConfig(new DataExtensionReconConfig(_columnTypes.get(i)));
+            	column.setReconStats(ReconStats.create(project, cellIndex));
             	
-            	Column column = new Column(_firstNewCellIndex + i, name);
-            
             	project.columnModel.columns.add(_columnInsertIndex + i, column);
             }
             
@@ -194,6 +214,17 @@ public class DataExtensionChange implements Change {
         for (String name : _columnNames) {
         	writer.write(name); writer.write('\n');
         }
+        writer.write("columnTypeCount="); writer.write(Integer.toString(_columnTypes.size())); writer.write('\n');
+        for (FreebaseType type : _columnTypes) {
+            try {
+                JSONWriter jsonWriter = new JSONWriter(writer);
+                
+                type.write(jsonWriter, options);
+            } catch (JSONException e) {
+                // ???
+            }
+            writer.write('\n');
+        }
         writer.write("rowIndexCount="); writer.write(Integer.toString(_rowIndices.size())); writer.write('\n');
         for (Integer rowIndex : _rowIndices) {
         	writer.write(rowIndex.toString()); writer.write('\n');
@@ -201,17 +232,22 @@ public class DataExtensionChange implements Change {
         writer.write("dataExtensionCount="); writer.write(Integer.toString(_dataExtensions.size())); writer.write('\n');
         for (DataExtension dataExtension : _dataExtensions) {
             writer.write(Integer.toString(dataExtension.data.length)); writer.write('\n');
+            
             for (Object[] values : dataExtension.data) {
             	for (Object value : values) {
-            		try {
-	            		JSONWriter jsonWriter = new JSONWriter(writer);
-	            		if (value instanceof ReconCandidate) {
-	            			((ReconCandidate) value).write(jsonWriter, options);
-	            		} else {
-	            			jsonWriter.value(value);
-	            		}
-            		} catch (JSONException e) {
-            			// ???
+            	    if (value == null) {
+            	        writer.write("null");
+            	    } else if (value instanceof ReconCandidate) {
+                        try {
+                            JSONWriter jsonWriter = new JSONWriter(writer);
+                            ((ReconCandidate) value).write(jsonWriter, options);
+                        } catch (JSONException e) {
+                            // ???
+                        }
+            		} else if (value instanceof String) {
+            			writer.write(JSONObject.quote((String) value));
+            		} else {
+            		    writer.write(value.toString());
             		}
             		writer.write('\n');
             	}
@@ -236,13 +272,18 @@ public class DataExtensionChange implements Change {
     static public Change load(LineNumberReader reader) throws Exception {
     	String baseColumnName = null;
     	int columnInsertIndex = -1;
-    	int firstNewCellIndex = -1;
+    	
     	List<String> columnNames = null;
+    	List<FreebaseType> columnTypes = null;
+    	
     	List<Integer> rowIndices = null;
     	List<DataExtension> dataExtensions = null;
+    	
         List<Row> oldRows = null;
         List<Row> newRows = null;
         
+        int firstNewCellIndex = -1;
+        
         String line;
         while ((line = reader.readLine()) != null && !"/ec/".equals(line)) {
             int equal = line.indexOf('=');
@@ -271,6 +312,14 @@ public class DataExtensionChange implements Change {
                     line = reader.readLine();
                     columnNames.add(line);
                 }
+            } else if ("columnTypeCount".equals(field)) {
+                int count = Integer.parseInt(value);
+                
+                columnTypes = new ArrayList<FreebaseType>(count);
+                for (int i = 0; i < count; i++) {
+                    line = reader.readLine();
+                    columnTypes.add(FreebaseType.load(ParsingUtilities.evaluateJsonStringToObject(line)));
+                }
             } else if ("dataExtensionCount".equals(field)) {
                 int count = Integer.parseInt(value);
                 
@@ -289,10 +338,12 @@ public class DataExtensionChange implements Change {
                             JSONTokener t = new JSONTokener(line);
                             Object o = t.nextValue();
                             
-                            if (o instanceof JSONObject) {
-                            	row[c] = ReconCandidate.load((JSONObject) o);
-                            } else {
-                            	row[c] = o;
+                            if (o != JSONObject.NULL) {
+                                if (o instanceof JSONObject) {
+                                	row[c] = ReconCandidate.load((JSONObject) o);
+                                } else {
+                                	row[c] = o;
+                                }
                             }
                     	}
                     	
@@ -325,6 +376,7 @@ public class DataExtensionChange implements Change {
     		baseColumnName, 
     		columnInsertIndex, 
     		columnNames,
+    		columnTypes,
     		rowIndices,
     		dataExtensions,
     		firstNewCellIndex,
diff --git a/src/main/java/com/metaweb/gridworks/model/recon/DataExtensionReconConfig.java b/src/main/java/com/metaweb/gridworks/model/recon/DataExtensionReconConfig.java
new file mode 100644
index 000000000..2ad72e612
--- /dev/null
+++ b/src/main/java/com/metaweb/gridworks/model/recon/DataExtensionReconConfig.java
@@ -0,0 +1,67 @@
+package com.metaweb.gridworks.model.recon;
+
+import java.util.List;
+import java.util.Properties;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+import org.json.JSONWriter;
+
+import sun.reflect.generics.reflectiveObjects.NotImplementedException;
+
+import com.metaweb.gridworks.model.Cell;
+import com.metaweb.gridworks.model.Project;
+import com.metaweb.gridworks.model.Recon;
+import com.metaweb.gridworks.model.Row;
+import com.metaweb.gridworks.protograph.FreebaseType;
+
+public class DataExtensionReconConfig extends StrictReconConfig {
+    final public FreebaseType type;
+    
+    static public ReconConfig reconstruct(JSONObject obj) throws Exception {
+        JSONObject type = obj.getJSONObject("type");
+        
+        return new DataExtensionReconConfig(
+            new FreebaseType(
+                type.getString("id"),
+                type.getString("name")
+            )
+        );
+    }
+    
+    public DataExtensionReconConfig(FreebaseType type) {
+        this.type = type;
+    }
+
+    @Override
+    public ReconJob createJob(Project project, int rowIndex, Row row,
+            String columnName, Cell cell) {
+        
+        throw new NotImplementedException();
+    }
+
+    @Override
+    public int getBatchSize() {
+        throw new NotImplementedException();
+    }
+
+    public void write(JSONWriter writer, Properties options)
+            throws JSONException {
+        
+        writer.object();
+        writer.key("mode"); writer.value("extend");
+        writer.key("type"); type.write(writer, options); 
+        writer.endObject();
+    }
+    
+    @Override
+    public List<Recon> batchRecon(List<ReconJob> jobs) {
+        throw new NotImplementedException();
+    }
+
+    @Override
+    public String getBriefDescription(Project project, String columnName) {
+        throw new NotImplementedException();
+    }
+
+}
diff --git a/src/main/java/com/metaweb/gridworks/model/recon/ReconConfig.java b/src/main/java/com/metaweb/gridworks/model/recon/ReconConfig.java
index 09909204b..d562d826d 100644
--- a/src/main/java/com/metaweb/gridworks/model/recon/ReconConfig.java
+++ b/src/main/java/com/metaweb/gridworks/model/recon/ReconConfig.java
@@ -21,6 +21,8 @@ abstract public class ReconConfig implements Jsonizable {
             return HeuristicReconConfig.reconstruct(obj);
         } else if ("strict".equals(mode)) {
             return StrictReconConfig.reconstruct(obj);
+        } else if ("extend".equals(mode)) {
+            return DataExtensionReconConfig.reconstruct(obj);
         }
         return null;
     }
diff --git a/src/main/java/com/metaweb/gridworks/operations/ExtendDataOperation.java b/src/main/java/com/metaweb/gridworks/operations/ExtendDataOperation.java
index 5d6e72e40..c7287f0c2 100644
--- a/src/main/java/com/metaweb/gridworks/operations/ExtendDataOperation.java
+++ b/src/main/java/com/metaweb/gridworks/operations/ExtendDataOperation.java
@@ -26,6 +26,7 @@ import com.metaweb.gridworks.model.changes.CellAtRow;
 import com.metaweb.gridworks.model.changes.DataExtensionChange;
 import com.metaweb.gridworks.process.LongRunningProcess;
 import com.metaweb.gridworks.process.Process;
+import com.metaweb.gridworks.protograph.FreebaseType;
 import com.metaweb.gridworks.util.FreebaseDataExtensionJob;
 import com.metaweb.gridworks.util.FreebaseDataExtensionJob.ColumnInfo;
 import com.metaweb.gridworks.util.FreebaseDataExtensionJob.DataExtension;
@@ -221,6 +222,11 @@ public class ExtendDataOperation extends EngineDependentOperation {
             		columnNames.add(StringUtils.join(info.names, " - "));
             	}
             	
+                List<FreebaseType> columnTypes = new ArrayList<FreebaseType>();
+                for (ColumnInfo info : _job.columns) {
+                    columnTypes.add(info.expectedType);
+                }
+            	
                 HistoryEntry historyEntry = new HistoryEntry(
                     _project, 
                     _description, 
@@ -229,6 +235,7 @@ public class ExtendDataOperation extends EngineDependentOperation {
                     	_baseColumnName,
                     	_columnInsertIndex,
                     	columnNames,
+                    	columnTypes,
                     	rowIndices,
                     	dataExtensions)
                 );
diff --git a/src/main/java/com/metaweb/gridworks/protograph/FreebaseType.java b/src/main/java/com/metaweb/gridworks/protograph/FreebaseType.java
index 434789fac..2ccc3911a 100644
--- a/src/main/java/com/metaweb/gridworks/protograph/FreebaseType.java
+++ b/src/main/java/com/metaweb/gridworks/protograph/FreebaseType.java
@@ -1,8 +1,36 @@
 package com.metaweb.gridworks.protograph;
 
-public class FreebaseType extends FreebaseTopic {
+import java.util.Properties;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+import org.json.JSONWriter;
+
+import com.metaweb.gridworks.Jsonizable;
+
+public class FreebaseType extends FreebaseTopic implements Jsonizable {
     public FreebaseType(String id, String name) {
         super(id, name);
     }
-
+    
+    public void write(JSONWriter writer, Properties options)
+        throws JSONException {
+    
+        writer.object();
+        writer.key("id"); writer.value(id);
+        writer.key("name"); writer.value(name);
+        writer.endObject();
+    }
+    
+    static public FreebaseType load(JSONObject obj) throws Exception {
+        if (obj == null) {
+            return null;
+        }
+        
+        FreebaseType type = new FreebaseType(
+            obj.getString("id"),
+            obj.getString("name")
+        );
+        return type;
+    }
 }
diff --git a/src/main/java/com/metaweb/gridworks/util/FreebaseDataExtensionJob.java b/src/main/java/com/metaweb/gridworks/util/FreebaseDataExtensionJob.java
index 3143b5826..41e0efa7f 100644
--- a/src/main/java/com/metaweb/gridworks/util/FreebaseDataExtensionJob.java
+++ b/src/main/java/com/metaweb/gridworks/util/FreebaseDataExtensionJob.java
@@ -23,6 +23,7 @@ import org.json.JSONObject;
 import org.json.JSONWriter;
 
 import com.metaweb.gridworks.model.ReconCandidate;
+import com.metaweb.gridworks.protograph.FreebaseType;
 
 public class FreebaseDataExtensionJob {
     static public class DataExtension {
@@ -36,10 +37,12 @@ public class FreebaseDataExtensionJob {
     static public class ColumnInfo {
     	final public List<String> names;
     	final public List<String> path;
+    	final public FreebaseType expectedType;
     	
-    	protected ColumnInfo(List<String> names, List<String> path) {
+    	protected ColumnInfo(List<String> names, List<String> path, FreebaseType expectedType) {
     		this.names = names;
     		this.path = path;
+    		this.expectedType = expectedType;
     	}
     }
     
@@ -130,7 +133,7 @@ public class FreebaseDataExtensionJob {
         int             startColumnIndex
     ) throws JSONException {
         String propertyID = extNode.getString("id");
-        String expectedTypeID = extNode.getString("expected");
+        String expectedTypeID = extNode.getJSONObject("expected").getString("id");
         
         JSONArray a = resultNode != null && resultNode.has(propertyID) && !resultNode.isNull(propertyID) ?
             resultNode.getJSONArray(propertyID) : null;
@@ -268,7 +271,7 @@ public class FreebaseDataExtensionJob {
     
     static protected void formulateQueryNode(JSONObject node, JSONWriter writer) throws JSONException {
         String propertyID = node.getString("id");
-        String expectedTypeID = node.getString("expected");
+        String expectedTypeID = node.getJSONObject("expected").getString("id");
         
         writer.key(propertyID);
         writer.array();
@@ -321,14 +324,20 @@ public class FreebaseDataExtensionJob {
         if (obj.has("properties") && !obj.isNull("properties")) {
             boolean included = (obj.has("included") && obj.getBoolean("included"));
             if (included && columns != null) {
-                columns.add(new ColumnInfo(names2, path2));
+                JSONObject expected = obj.getJSONObject("expected");
+                
+                columns.add(new ColumnInfo(names2, path2, 
+                    new FreebaseType(expected.getString("id"), expected.getString("name"))));
             }
             
             return (included ? 1 : 0) + 
             	countColumns(obj.getJSONArray("properties"), columns, names2, path2);
         } else {
             if (columns != null) {
-                columns.add(new ColumnInfo(names2, path2));
+                JSONObject expected = obj.getJSONObject("expected");
+                
+                columns.add(new ColumnInfo(names2, path2,
+                    new FreebaseType(expected.getString("id"), expected.getString("name"))));
             }
             return 1;
         }
diff --git a/src/main/webapp/scripts/dialogs/extend-data-preview-dialog.js b/src/main/webapp/scripts/dialogs/extend-data-preview-dialog.js
index 5fbcfb424..c6b66c5a6 100644
--- a/src/main/webapp/scripts/dialogs/extend-data-preview-dialog.js
+++ b/src/main/webapp/scripts/dialogs/extend-data-preview-dialog.js
@@ -64,6 +64,7 @@ ExtendDataPreviewDialog.getAllProperties = function(typeID, onDone) {
                 "name" : null,
                 "/type/property/expected_type" : {
                     "id" : null,
+                    "name" : null,
                     "/freebase/type_hints/mediator" : []
                 },
                 "sort" : "name"
@@ -74,6 +75,7 @@ ExtendDataPreviewDialog.getAllProperties = function(typeID, onDone) {
             "name" : null,
             "/type/property/expected_type" : {
                 "id" : null,
+                "name" : null,
                 "/freebase/type_hints/mediator" : []
             },
             "sort" : "name"
@@ -90,7 +92,10 @@ ExtendDataPreviewDialog.getAllProperties = function(typeID, onDone) {
             allProperties.push({
                 id : property.id,
                 name : property.name,
-                expected : expectedType.id
+                expected : {
+                    id : expectedType.id,
+                    name : expectedType.name
+                }
             });
         }
     };
@@ -137,7 +142,8 @@ ExtendDataPreviewDialog.getAllProperties = function(typeID, onDone) {
                     "id" : null,
                     "name" : null,
                     "/type/property/expected_type" : {
-                        id : null,
+                        "id" : null,
+                        "name" : null,
                         "/freebase/type_hints/mediator" : []
                     },
                     "sort" : "name"
@@ -150,15 +156,24 @@ ExtendDataPreviewDialog.getAllProperties = function(typeID, onDone) {
                 function(o2) {
                     if ("result" in o2) {
                         var processCVTProperty = function(parentProperty, properties) {
+                            var parentExpected = parentProperty["/type/property/expected_type"];
+                            
                             $.each(properties, function() {
+                                var expected = this["/type/property/expected_type"];
                                 allProperties.push({
                                     id : parentProperty.id,
                                     name : parentProperty.name,
-                                    expected : parentProperty["/type/property/expected_type"].id,
+                                    expected : {
+                                        id : parentExpected.id,
+                                        name : parentExpected.name
+                                    },
                                     properties: [{
                                         id : this.id,
                                         name : this.name,
-                                        expected : this["/type/property/expected_type"].id
+                                        expected : {
+                                            id : expected.id,
+                                            name : expected.name
+                                        }
                                     }]
                                 });
                             });
@@ -204,10 +219,14 @@ ExtendDataPreviewDialog.prototype._show = function(properties) {
     };
     
     this._elmts.addPropertyInput.suggestP(suggestConfig).bind("fb-select", function(evt, data) {
+        var expected = data["/type/property/expected_type"];
         self._addProperty({
             id : data.id,
             name: data.name,
-            expected: data["/type/property/expected_type"]
+            expected: {
+                id: expected.id,
+                name: expected.name
+            }
         });
     });
 };
diff --git a/src/main/webapp/scripts/util/custom-suggest.js b/src/main/webapp/scripts/util/custom-suggest.js
index 024f844b8..1e483ea9d 100644
--- a/src/main/webapp/scripts/util/custom-suggest.js
+++ b/src/main/webapp/scripts/util/custom-suggest.js
@@ -127,7 +127,7 @@
                 mql_output: JSON.stringify([{
                     "id" : null,
                     "name" : null,
-                    "/type/property/expected_type" : null
+                    "/type/property/expected_type" : { "id" : null, "name" : null }
                 }])
             };
             if (start) {