[apowers]

To answer that question, none of the computing power is used towards anything but verifying transactions and - the real work here - solving hashes to generate more bitcoins.

There's plenty of discussion on what this cloud-supercomputer could be doing in addition to its current task. Problem is, the nature of mining introduces several limits on the types of computational problems miners try to crack.

https://bitcointalk.org/index.php?topic=203.msg3669#msg3669

Here's a post describing the qualities a bitcoin-appropriate computational problem would have.