Circle is one of the most notable features of Google Plus, it allows users to manage and create friends lists by dragging them into circles. While Google Plus hasn’t been officially launched, there are already the clone of Google Plus Circle on Facebook.
Circle is particularly useful because it helps classify the relationships from the start, such as friends, co-workers or following. Each Circle is like a small community, in which members have the same interest or relationship, that makes Google Plus become more private than Facebook without losing the features of a social network. We can still manage relationships on Facebook by using the Manage Friend List option, however, this is less known and less intuitive than Circle.
Then, 4 Facebook engineers created an app called Circle Hack so that users can experience the interesting classification feature. This is not an official app of Facebook. To use Circle on Facebook, we just need to go to the site CircleHack, then log in to Facebook. After agreeing to use this application, you will see a page similar to Google Plus Circle, it includes a list of all your friends and circles below. Then, you just drag and drop friends into the circles, you can also change the name, size or add new circle.