Once users sign up for FriendFeed and invite some friends, they get a customized feed of the content shared by their friends---from news articles to family photos to interesting links and videos. For example, if your friend favorites a video on YouTube, you get a link and a thumbnail of the video in your feed. And if your friend likes a news story on Digg, you get a link in your feed.

You don't need to install anything to use FriendFeed; you cann add it to your Facebook account, view it in your Google home page or read it in a feed reader.  You can also make your feed publicly available by embedding your feed in your home page or blog.