Google posted a press release confirming that they have partnered with several large social networks including MySpace. As you have likely read already, these sites are adopting the "OpenSocial" platform -- it will be a shocker if developers don't flock to it. Having had the pleasure to working with the API while it was being created, I can say that it has turned out great, and my hats go off to the engineers at Google who made it possible.
If you are a developer, keep your eyes on http://code.google.com/apis/opensocial. Currently, this page only gives an error, but soon it will have lots of good documentation about how you can go about creating your own social gadgets for the new platform. If you already have a Facebook application, in most cases porting it over to the OpenSocial platform will be fairly painless -- but it will still take a some effort.
OpenSocial was due to be released on November 5th, so I guess we will get it four days earlier than expected. It will be very interesting to see if Facebook joins the OpenSocial alliance or decides to remain a proprietary social network that is determined to make it on it's own. What do you think? Should Facebook give in to the pressure or not?