It is Plura, and while you can technically get paid for it, it's not really worth it for an individual. However, if you can bring hundreds or thousands of computers to the grid by embedding it in an application, then the payments can be significant.
"[...] in fact was announced on the Digsby blog as an official way they are going to make some money, with Plura Processing as a partner."
As to whether or not you can supply processing power for a fee, I doubt it. Looking through their individuals page briefly it looks like it's very similar to SETI@home or any other distributed computing effort. If you like the projects they're running you help, if not you don't.
