ET
Previous searches by SETI@home have looked for extraterrestrial communications in the form of narrow-band signals, analogous to our own radio stations. The Astropulse project argues that since we know nothing about how ET might communicate, this might be a bit closed-minded. Thus, the Astropulse survey can be viewed as supplementing the narrow-band SETI@home survey as a by-product of the search for physical phenomena.
Read more about this topic: Astronomical Radio Source