Facetime was supposed to become an open standard†, but I don't think Apple ever said that about imessage. † From the WWDC 2010 keynote: “And we're going to tak

Facetime was supposed to become an open standard†, but I don't think Apple ever said that about imessage. † From the WWDC 2010 keynote: “And we're going to take it all the way. We're going to the standards bodies, starting tomorrow, and we're going to make Facetime an open industry standard.”