I think it was to be expected in Asia, with China blocking them, but the real surprise was that people are <i>quitting</i> it in its core market: North America. And that was even before Google+ was announced. The launch of Google+ will only accelerate the exodus, because I believe there are a lot of Facebook early adopters who got tired of it, and they couldn't wait to move on to the next big thing. Unfortunately, until Google+ there was no such thing.
Not sure where there is really the news. With a limited number of humans and a percentage of social media users of X% of human population, this needs to slow. The slowing down seems to come early, but only because FB is such a huge success.