1. A computer-implemented method for expanding search results, at least a portion of the method being performed by a computing device comprising at least one processor, the method comprising: identifying, within results of a search, a document that is a member of a document family that includes at least one other document; determining that a user has made a selection to include, within the results of the search, the document family; creating a data map that includes a representation of the document identified within the results of the search at least in part by identifying a unique identifier associated with the document that corresponds to an offset within the data map and representing the document by toggling a bit at the corresponding offset on the data map; based on the determination that the user made the selection, expanding the data map by including, within the data map, a representation of each of the at least one other document in the document family; using the expanded data map to include the document family within the results of the search.
2. The method of claim 1 , wherein: determining that the user made the selection to include the document family in the results of the search comprises determining that the user made the selection, before performing the search, to include each document family that includes any document found in the search; expanding the data map comprises including, within the data map, each document family that includes any document found in the search; using the expanded data map to include the document family within the results of the search comprises including, within the results of the search, each document family represented on the data map.