There are two reasons I run seti@home. First, I don't like wasting. Included is unused CPU cycles. Second, as the systems administrator at the company I work for, I get the last say on what can and cannot run "my" computers. (Of course this does not decrease productablity :-)
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.