[djsumdog]

Yep, it was originally run by Carnegie Mellon (as you mentioned, by its creator Luis von Ahn and others).

This article also doesn't seem to touch on the newer reCaptcha that tracks you everywhere on a website (you'll notice a little blue box on the bottom right with the logo where this happens), not just on login or user input pages.

There is a lot to criticize about reCaptcha, including privacy concerns for sure, and there were some other posts about it on HN before.