Plaxo has just announced that OpenSocial is live at Plaxo Pulse. They say it's still in version 0.5 and so bumps are expected. Last week's announcement of the Plaxo lifes-tream widget was just a small component of this growing OpenSocial movement.
In addition, we've built OpenSocial gadget support into our new Dynamic Profiles feature, which means just as you can now show a separate profile (photo, bio, contact info, interests, etc.) to your business contacts and your friends, you can also add gadgets separately to your professional and personal profiles, and also control which sets of contacts see the activity streams from those gadgets. So if you just want to emote with your friends and not your business colleagues, now you can!
If Plaxo is already leveraging this API to allow the differentiation of contact information in its first iteration, we're going to see a lot of people moving into this space. That is precisely the issue many have had with Facebook: you can't differentiate between your contacts.
This is going to be an interesting week.