This is why I have my blog auto-post ton Twitter (and from there, on to Facebook) - otherwise, all that content is owned by someone else, and - if the service(s) in question die off, you're left with nothing. As Leo Laporte just realized:

It makes me feel like everything I’ve posted over the past four years on Twitter, Jaiku, Friendfeed, Plurk, Pownce, and, yes, Google Buzz, has been an immense waste of time. I was shouting into a vast echo chamber where no one could hear me because they were too busy shouting themselves. All this time I’ve been pumping content into the void like some chatterbox Onan. How humiliating. How demoralizing.

I use (or used, when they still existed) many of those - but I've always kept my blog (first the corporate one, and now, this one) front and center. That way, I have control over my own web history.