9 popular social information aggregation sites

At present, Twitter, Friendfeed and Google Reader have become the main channels for more and more people to share information, but in the case of more and more information, information overload has become a serious problem, we already have too many information aggregation and sharing channels. The filtering and screening of information becomes an even more valuable service. Based on Twitter's RT function, Google Reader's sharing function, using this social Digg function, you can dig out the hot information that everyone is concerned about, but also let us get more valuable information through less reading time. Here are 9 social aggregators that I know are based on Twitter, friendfeed, and Google Reader.