A social data aggregator generates entries of action data describing actions taken by users. A portion of the entries are stored in an action cache to expedite retrieval. To store more recent or relevant entries in the action cache, entries are removed from the action cache based on engagement scores associated with the entries. An engagement score indicates a likelihood of a user requesting content interacting with a notification based on an entry. Entries having the lowest engagement scores or having engagement scores below a threshold are removed from the action cache.