Facebook today made a huge announcement that they would have their own open application platform – putting it in direct competition with Google’s OpenSocial. While there had been some speculation as to whether Facebook would eventually fall in line with seemingly just about everyone else and join OpenSocial, I noted in the beginning of November that an all-out Social Networking War was upon us between Facebook and Google – something which Mathew Ingram backs up today.

Bebo immediately signed on board with Facebook (even though they’re already supposedly on board with OpenSocial as well) and Nick O’Neil wonders about the others in a very Magneto in X-Men 3 type way: “Who will you stand with?“. Interestingly Yahoo! immediately jumped on to make applications for Bebo with this announcement – take from that what you will.

But I for one still see this as very much a proxy war to the larger Microsoft/Google War. Microsoft of course beat out Google to invest in Facebook in October, and at least part of that was likely due to the events we now see unfolding before us. Facebook had it’s own advertising platform it wanted to launch – something which Microsoft was no doubt more receptive to than Google – and they had no intention of falling in line with a Google-run social networking toolkit when they had such a successful one of their own already.

Up until now in the Microsoft/Google war, things had largely gone Google’s way as Microsoft continues to fumble its way toward competency in the online realm. This new Social Proxy War could have a much different outcome however with Facebook thus far in the much better position as Google struggles to get OpenSocial out the door.

Yes, Microsoft’s stake in Facebook is relatively minor, but it’s still a stake and it blocked Google from gaining access to the hottest social network in the world right now. The question may ultimately be: are you a Microsoft Man or a Google Guy?