Because I have always been interested in what SETI tries to acomplish. I think that the day will come when SETI will be sucessful and want to know that I had a very small part in that.
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.