An anonymous reader writes "I am a big fan of Oodle, the online classifieds aggregator. I was disheartened when Craigslist announced that they would block Oodle from their site in late 2005 (old link), as I find their service very handy. I came across this page at the site of an aggregator of freelance job openings that summarizes the arguments around the legality of meta search engines and mashup-like sites and I found myself wondering if Oodle could have avoided the ban. There is an interesting argument there that seems to undermine copyright claims of user-generated content compilations. Are mashups legal? How does this affect sites like Digg or YouTube?"