This is a impressive and (deceptively) simple webapp that allows you to route actions in a service (eg. liking a video on YouTube) to another (eg. tweeting about it). Granted, many sites offer this ability already, but I like IFTTT because it provides a central dashboard for all your routing while often being more customizable. Sure you could use Yahoo Pipes or Tarpipe, but those are just too excessive. Here’s a list of IFTTT recipes.