Google Reader works by constantly checking your feeds you subscribe to for new content. This way you won’t miss any updates and with the service being online you won’t loos all your feeds if your PC crashes!
If you already have a Google account you can use the same details to log into Google Reader. It also has some nice features like sharing & rating feeds. If you want something fast and simple look no further this is the RSS reader for you.
Here’s what it looks like: