The button will appear on the profiles of your friends and other users. It allows you to do 3 things: control what you see from your friends in your News Feed; add public posts from people you are not friends with to your News Feed; and let others subscribe to your public posts.
First, the button lets you manage how much content you see from your friends. You can choose to see all of their updates; most of their updates (i.e. the updates you normally see from them); or just the most important updates, like when their relationship status changes or they get a new job. You can also select what type of updates you want to see. So, for instance, if you have a friend you mostly play games with on Facebook, you can choose to only see stories about games from them. You may also opt not to see photos from someone who shares too many images in your feed. You can decide whether you see stories on life events, status updates, photos and videos and games for each person. It should be noted that nothing will change in your News Feed unless you want it to. So if you don’t want to change what you are seeing from someone, simply ignore the button.
The second way to use the Subscribe button is to add content from people you are not friends with but still find interesting into your News Feed. For instance, you might want to see posts from your favorite bloggers, celebrities, journalists or artists in your News Feed, which you can do by subscribing to them. As with your friends, you can choose what types of content you want to see and how much you’d like to see from each person you have subscribed to. Facebook will also suggest people for you to subscribe to based on how many of your friends subscribe to that person and how many interests you have in common.
Lastly, people can subscribe to your posts too so you can share your status updates, links, photos, questions and more with more than just your friends. People who are subscribed to you but whom you are not friends with will only see posts you share publicly. If you would like to allow other Facebook users you are not friends with to subscribe to your public posts, you can enable the Subscription button on your profile by clicking “Allow Subscribers” from the Subscriptions Page.
Once you have added the button, you can also decide who can comment on your posts and what notifications you receive from the Subscriptions tab on the left of your homepage. Additionally, you are able to see who has subscribed to you in the tab. If there is someone who you do not want to subscribe to your posts, you can choose to block them from your account. You can manage your subscriptions — for both your friends and others — from the Subscriptions tab.
The launch of the Subscribe button is big for several reasons. One being that there is no limit on the number of subscribers you can have, so you can effectively say goodbye to the 5,000 friend limit if you want to share content with a lot of people (though you can only subscribe to a maximum of 5,000 people). Of course, you could always set up a personal Facebook Page to share content, but many users will simply find it easier to share on their profile rather than having to share content on both their profile and a page. Pages will still exist as they provide an important social marketing platform for brands, companies and products (Facebook has a post on the differences between pages and the Subscribe button) but the Subscribe button effectively allows others to Like your profile and see your personal public posts.
As ever, Facebook suggests that you only add people as friends when you know them personally, but the Subscribe button allows you to find out what individuals are sharing without having to be friends with them. The button will only appear on your profile if you enable it, but you will automatically see the subscribe button on your friends’ profiles (you’re already subscribed to their posts anyway, by virtue of being friends with them) so you can choose what content you want to see from them.
It seems to me that Facebook is trying to shift the way in which people use the social network. By adopting a Twitter-like follow model, it seems that Facebook is trying to open up the network a little more and encourage people to share more content publicly. For instance, my Facebook profile is for friends and family only. I don’t share many posts publicly and this holds true for many other users. However, I’m starting to rethink that policy and might start posting more content publicly from my profile.
I would think that, with the Subscribe button and revamped Friend Lists feature that was launched Monday, Facebook is trying to kill off Twitter and Google+ by mimicking features of those services on the world’s largest social network. I don’t think that Facebook will completely kill off Twitter and Google+, as the services have different audiences. However, these features may have a significant impact on Twitter and Google+ usage going forward.