I guess at least some people are familiar with the concept but it is good to spend some more time thinking over it, especially in the light of what is going on now
http://hanson.gmu.edu/greatfilter.html
(click on the link, it is better formatted)
http://www.350.org/4/?page_id=19
http://www.tomdispatch.com/post/174930/bill_mckibben_the_defining_moment_for_climate_change
The World at 350
A Last Chance for Civilization
By Bill McKibben
good article
http://www.seedmagazine.com/news/2008/04/suspending_life.php?utm_source=SB-bottom&utm_medium=linklist&utm_content=magazine&utm_campaign=internal%2Blinkshare
interesting hypothesis
the creationists better stay away from the thread
http://scientificblogging.com/news_releases/did_a_meteorite_cause_the_existence_of_left_handed_amino_acids