Facebook appears to be testing a “subscribe to page” button on page-Like stories in News Feed.
With subscribe, users can receive News Feed updates from a page without indicating that they “Like” it. They can also add pages to interest lists to get a separate feed of posts on a particular topic. It is unclear how pages that a user subscribes to are factored into ad targeting or whether subscribers are more likely to see page posts than fans who Like the page are. Facebook could be planning future changes to distinguish Like from Subscribe.
Facebook introduced subscribe for personal accounts in September 2011 to allow for asymmetric relationships between users. Last month, some Facebook users began to see a subscribe button on business pages. That hasn’t rolled out to all users, but now some users who can’t see the subscribe button on pages are seeing the option below News Feed stories.
A week ago, Facebook added subscribers to insights so page owners can see how many people are following their page this way. It seems that only users who clicked the subscribe button are counted in this metric, not users who follow the page via an interest list. There still isn’t a way for admins to see which interest lists their pages are included on, though Facebook gave this option to personal profiles in June.