Buffy - June 2007
In honor of Vanessa Fox leaving Google, the "Buffy" update was christened. No one was quite sure what happened, and Matt Cutts suggested that Buffy was just an accumulation of smaller changes.
Google "Buffy" Update - June Google.com Update (SERoundtable)
SMX Seattle wrap-up (MattCutts.com)
Universal Search - May 2007
While not your typical algorithm update, Google integrated traditional search results with News, Video, Images, Local, and other verticals, dramatically changing their format. The old 10-listing SERP was officially dead. Long live the old 10-listing SERP.
