Techniques are described for effecting data aggregation in a network. Event notifications are received from a plurality of content sites on the network. Each event notification indicates occurrence of an event associated with a corresponding one of the content sites. Each event corresponds to a change to content associated with the corresponding content site. In response to each event notification, event metadata are generated. The event metadata include a time stamp for the event and change data corresponding to the change to the content. The event metadata are indexed in a plurality of databases with reference to a plurality of index metrics including the time stamp. The indexing of the event metadata for each event occurs within days, hours, or even minutes of receipt of the corresponding event notification thereby enabling retrieving of the changes to the content from the plurality of databases using any of the index metrics in near real time.