When the OpenSocial project was announced, I imagined that it would either knock Facebook from its top position or force Facebook to join in.  As the months went by, I started to doubt that OpenSocial was as important as it first seemed.  But now, with the launch of the iGoogle sandbox, I'm starting to believe again in the potential of OpenSocial to change social networking.  Just as developers scrambled to develop applications for Facebook, I think that they'll now scramble to develop OpenSocial applications to put on iGoogle, MySpace, Ning, etc., etc.  My guess is that Facebook will join in, rather than get left behind.