Following Feature in SharePoint 2013

SharePoint 2013's Following Feature keeps you connected to the things that you care about the most.

There are four things that you can follow: People, Documents, Sites, and #Tags.

The vision for this release was that when you follow any of these four items, three things would happen:

1. You'd have a rich, aggregated view where you could easily access the set of followed things and see additional information about those things.
2. You'd promote serendipitous discovery of new people and content through the posting of a "User is now following Item" post to all of your followers (if your privacy is set accordingly).
3. You'd see future updates about what you followed in the Following view of your Newsfeed.

Read more from source: http://sharepoint.microsoft.com/blog/Pages/BlogPost.aspx?pID=1060