Apparently it’s embrace the developer community day at Facebook. In addition to the news that they are making activity stream data available to third party developers, they’ll also be making an announcement around OpenID, we’ve heard. And importantly, the announcement is that they’ll become what’s called a relying party, meaning anyone with an OpenID (Yahoo, Google, AOL, MySpace are all issuers, and Microsoft is in beta) can create and log into a Facebook account using those credentials.