Human-Checking Test: Useful in more ways than one...

Anyone who's spent much time on the internet has encountered "human-checking" at some point - usually typing in a series of letters seen twisted, faded, grainy, and crazy in a barely-readable image. Machines aren't very good at this kind of thing (or at least there a little worse that humans), so these tests can prove that a user is a real person and not a spam-bot. It's effective, if a bit annoying.

Fortunately, a great way to wash away the foul aftertaste of annoyance is with a sweet swig of inspiration. Enter ReCAPTCHA (via Gizmodo), which feeds images of words scanned from books that the automatic scanner couldn't quite read. Now, by verifying your humanity, you're also helping humanity by contributing to the accurate digitization of the world's libraries. Not only that, but rather than typing the random strings of characters which made the old version of the task even more irksome, you're typing in real words! Of course, you just might be too inspired by the cause to even notice.