Glue Toolbar

File under “Good ideas that Facebook needs to steal, because in the current market a small start-up will never reach the critical mass needed for it to work” (although Facebook has already screwed the pooch as far as interaction with third-party websites is concerned): Glue is a Firefox toolbar that recognizes when you’re viewing a web page about a book, movie, restaurant, and so on, and displays reviews about it from your friends — and it works even if you’re looking at a movie page on Amazon and a friend of yours reviewed it while visiting the IMDb (hence the plug-in’s name). But it doesn’t work if your friends aren’t using Glue.