I signed up to seti@home because I always oc my PC's and I like to get out the very best of a system! Therefore it's very nice to have a programm that gives your PC something to do and you something to compare stats.
So that's my main opinion on seti.
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.