Feeding frenzy

Abstract

Near real-time event streams are becoming a key feature of many popular web applications. Many web sites allow users to create a personalized feed by selecting one or more event streams they wish to follow. Examples include Twitter and Facebook, which a user to follow other users' activity, and iGoogle and My Yahoo, which allow users to follow selected RSS streams. How can we efficiently construct a web page showing the latest events from a user's feed? Constructing such a feed must be fast so the page loads quickly, yet reflects recent updates to the underlying event streams. The wide fanout of popular streams (those with many followers) and high skew (fanout and update rates vary widely) make it difficult to scale such applications.