There have been surprisingly fast developments in the brewing war over social networking open standards involving Facebook and Google’s FriendConnect and OpenSocial, which I first referenced in last week’s post on Microsoft’s possible rationales for soon making an offer for Facebook.

Facebook on Tuesday announced "fbOpen" as its competing OPEN standard for building Facebook compliant social networks. I would expect that a competitor to Google’s FriendConnect for accessing Facebook’s (and other compliant social networks’) social graph information, if not already included, is soon to follow.

How nice of them to be complying with my recent prediction so quickly… as for the other shoe to drop and Microsoft buying them, we’ll see.

Here’s what I said May 16 on Microsoft’s options:

… Buy Facebook and VERY QUICKLY throw weight behind Facebook’s API as a competing standard to OpenSocial in opening up the “walled garden” of Facebook in strategic ways.

Given Facebook’s recent loss of developer energy and possible setting in of some user boredom, in reality this move is not much of a surprise per se, but the speed of the reaction is. This goes to show that mind-set and mind-share are everything in this new Attention Economy of Web 2.0 and beyond.

Facebook just couldn’t afford to let Google own the "open social network API" category and run away with things. So they had to reverse course and open up their social graph. We’ll soon know if Microsoft thinks it can afford being without a credible stake in the social networking space as a whole. (And no, their "Live Spaces" offering is NOT a credible stake.)

My bet is on them buying Facebook, and quickly.

I was reminded today that Rupert Murdoch did the MySpace deal in one weekend back in 2005. And despite the recent MySpace plateauing (at least in the U.S.) until about the beginning of this year when they made their moves on MySpace apps and a more solid API footing supporting Google’s OpenSocial, the then $580M price tag must appear like the steal of the century now that Facebook might go for $15B+.

Given that Micro-hoo negotiations appear to have more thoroughly collapsed for the time being (both sides have made statements in the last week or so that things were never as close to a deal as assumed before Ballmer’s pull-out, with both Bill Gates and key Yahoos presumably holding serious reservations), Microsoft does have a lot of cash burning a hole in it’s pocket.

More on that continuing saga later. I still owe you "Micro-hoo: The Post-Mortem Post Part II", only the developments are moving faster than I can write… intelligently…