The reddit thread [1] explains that the worm was posting information on /r/minecraftserverlists, presumably as a way to easily, anonymously, and publicly store and retrieve information.
Just last week in the thread on the twitter image bots [2] someone postulated:
>I wonder if you could build some kind of distributed neural net on top of twitter or another social network. Find some way to get nodes with very little computation power hidden within a free app, webpage, screensaver or something[1], and use twitter as a communications channel instead of IRC or whatever.
...
> Or a botnet, if you're feeling evil.
[1]http://www.reddit.com/r/news/comments/2i6rte/hackers_have_fo...