The 'Subscribe' button is similar to Twitter's Follow feature and somewhat similar to Google+ 's Add to Circle option. The person to whom you subscribe need not have to accept like in a friend request. But the person who subscribes to you will be able to view all the public updates on his news feed. Additionally, you can also view profiles of the people who have subscribed to you which means, no secret followers. Facebook in one of its post explains this feature to be most useful to celebrities. It says -
It is most useful for public figures like journalists, artists, and local politicians. For example, if you’re a journalist, you can use a profile to share your press coverage with your readers and ask them to post tips to help guide your research and investigation.
This is really good because celebrities and popular figures need not have to accept friend requests from infinite fans neither the fans have to wait for their friend request to be accepted. This feature is likely to attract more celebrities to appear on facebook.
If you want to have a Subscribe button on your facebook profile page, then you have to go to this site facebook.com/about/subscribe and click on "Allow Subscribers". This will enable the Subscribe button on your profile.
Ever since Google+ is released, facebook is on a spree of rolling out new features. The features provided by both the giants are more or less the same. Online forums are already discussing the genuineness of features as to who first introduced which feature. The discussion is taking egg or hen pattern, as no one knows which one came first, the egg or the hen. Same is in this case, no one can really tell who copied which part of the feature from whom.
