Today Facebook announced that it is going to become an OpenID Relying Party (RP) which means that anyone with an OpenID (AOL, Google, MySpace, Yahoo) and Microsoft (in beta) can create and log into a Facebook account using those credentials. This is big news as now one of the largest social networks will be OpenID-enabled.Since early 2008 we have seen all the major identity providers becoming issuers of OpenIDs (AOL, Yahoo, Google, MySpace and soon Microsoft). By the end of 2008 and early 2009 we started to see an increase in websites accepting users with these OpenIDs to login. As many of you know, JanRain launched its RPX solution to easily enable websites to accept both OpenIDs and proprietary protocols like Facebook Connect and Windows Live IDs. We expect that other large web properties are realizing, like Facebook, that lowering the barrier to login is essential to an enhanced customer experience on their site.Congrats to the Facebook team!