LeechBlock is a Firefox extension that blocks time-wasting websites that you manually specify. One of the nicest features for those of us who use multiple computers is the ability to load the block list from a URL. I put together a simple web interface for maintaining such block lists:
http://leechblocklist.appspot.com/It's useful even if you just want to maintain your own list, but possibly more useful in that it maintains a list of sites that are commonly thought to be time-wasting. Or, it will, if a few more people start using it.
