Various components and processes are provided to enable data processing on multiple data types where aspects of the history of user activity, attention, interest, location, or other interaction with data is determined and employed to enhance information storage and access. In one particular aspect, a data manipulation system is provided. The system includes one or more data items that are associated with one or more tags and indicate at least one user's interaction or activity with the data items. A manipulation tool that processes the data items to determine a subset of data items based at least in part on the user's interaction with the data items. Methods are described for using the manipulation tool to weight terms in an index, to compress indexes, to influence the rank of items returned in a search, to generate additional queries for data items either automatically or with user direction, or for improved presentation of data items.