I run SETI@home because I believe that assisting the SETI project is a worthwhile use of my spare computering power, and I have always been interested in knowing more about what lies "out there"...
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.