In SharePoint 2013 we have a great social tagging functionality out of the box actually there are four things that we can follow:
The vision for this release was that when we follow any of the above four items, three things would happen:
We would have a rich, aggregated view where we can easily access the set of followed things and see additional information about those things.
We would have promoted 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).
Follow the following MS thread for more explanation
This is awesome, surly we can compete to Facebook and twitter 🙂 in office 🙂