The Spark of Searching for Extraterrestrial Life

Charlie Stross pointed out an article and commentary that peaked my interest, dealing with SETI and the Fermi Paradox. The article was The Fermi Paradox, Self-Replicating Probes, and the Interstellar Transportation Bandwidth by Keith Wiley. Wiley's article was to do with the likelihood of Intelligent Aliens or lack thereof. 

If you aren't familiar with the Fermi Paradox, it basically states that the likelihood of intelligent life in the galaxy is high, given the huge number of stars and therefore planets in our galaxy, that intelligent extraterrestrial life should have been to visit us by now or at least left their evidence and yet we haven't found clue one.  There are lots of theories as to why and these essays delve into those arguments.