Facebook's Subscribe Button: A Getting-Started Guide
If you would like to allow subscribers to view your public updates, the easiest way to activate this feature is to visit the Facebook Subscriptions page and click "Allow Subscribers." After you allow subscribers, a dialog window will appear where you can set two preferences related to public subscriptions: commenting rules and new subscriber notifications.
By default, only your friends and friends of friends can comment on your public updates. But you can choose to allow anyone to comment on your public updates by selecting "On" from the dropdown menu in the Comments section of the dialog.
For new subscriber notifications, you can choose to be alerted when anyone subscribes to your updates, only when friends of friends subscribe or you can turn off new subscriber notifications entirely. By default, notifications are set to friends of friends.
Facebook will allow an unlimited number of people to subscribe to your public updates, but you can only subscribe to a maximum of 5,000 people.
Setting public updates
On the Web, you can set public updates in the content sharing entry box at the top of your Facebook home page by clicking on the cog next to the Post button. Facebook's mobile apps also have options for setting status updates to public or just friends.
But there are a few things to note about going public. First, once you set an update to Public (meaning anyone on Facebook could potentially see it) all your updates will be set to Public until you change this setting back to Friends or Custom. Also, if you are using Facebook's custom function for your updates, you will lose your settings entirely when you decide to share a public update. Meaning that every time you share a public update, you will have to reenter your custom settings when you switch back.
If you want to block a subscriber from your updates because of harassing comments or other unwanted behavior, click on "Account" on the top right of your profile and select "Privacy Settings." On the next page, scroll down to the bottom and click on the "Manage Blocking" link in the "Blocked People and Apps" section. From there you can enter a user's name or e-mail address to block them from viewing your updates.
Facebook has been hard at work adding new features to its services leading up to the social network's F8 developer conference next Thursday. Facebook recently revamped its friends list feature that is supposed to make it easier for you to group friends into different categories similar to the Google+ Circles feature.