http://postedyet.com
Posted Yet helps you find out if a site you are visiting from one news site has been posted to others. I'm currently indexing the popular stories on Digg, Reddit, BoingBoing and Hacker News. Just enter the site's URL into the form or use the Greasemonkey / GreaseKit / bookmarklet scripts below. Clicking on the results will take you to the comments/discussion area for the posting.
Examples of cross posts from recent HN posts.
Video Lectures: http://postedyet.com/?u=http://linkmingle.com/list/30-plus-List-of-Computer-Science-Video-Lectures-Over-200-Videos-video-lectures
M.I.T. students make huge parabolic mirror: http://postedyet.com/?u=http://www.dailytech.com/MIT+Students+Develop+Revolutionary+Solar+Dish+That+is+Hot+Enough+to+Melt+Steel/article12153.htm
George Carlin's passing: http://postedyet.com/?u=http://www.msnbc.msn.com/id/25322638/
Using the bookmarklets or Greasemonkey scripts would allow you to bypass coming back to the homepage.
The site has been tested in Safari 3.1.1 and Firefox 2. If you experience any issues please let us know which browser/OS combination you are using and we will fix it.