I'm very excited to try this out. Context (AKA "Circles") is the biggest feature Facebook still hasn't gotten right. By mirroring the way we think about our social graph in real life, Google is making a huge step toward converging Online and Offline identity. It will be very interesting to see how Facebook responds to this... they might finally have a competitor.
Paul Adams, the previous social research lead in the Google UX team, explained why context matters in this very interesting presentation (12 months old!):
According to his blog ( http://www.thinkoutsidein.com/blog/ ), he now works at Facebook, and focuses "on researching and designing better ways for businesses and people to communicate and interact". My guess is that Facebook is already preparing its response...
Facebook has gotten increasingly harder and more convoluted to manage. Case in point: no direct way to edit the photos in an album. Used to be so easy.
