I think Carl Sagan said it best, If we are alone it would "be a terrible waste of space." Anything I can do to help the project, I try. Since I can't give them a bunch of money, I run the client on as many machines as I can.
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.