JANUARY 11, 2009
An activity stream is a mash-up of an individual’s or organization’s feeds. For example, my FriendFeed pages show activity from this blog, the Internet Time Blog, my Flickr account, bookmarks I put on Delicious, and my entries from Twitter. Tumblr operates similarly although it does a better job displaying photos and is a bit more spartan. Activity stream aggregators typically republish activities in reverse chronological order, independent of type of activity.