When Facebook launched the “Subscribe” feature after F8, it was met with universally positive feedback. Any users who opted into Subscribe could allow non-friends to subscribe to their public profile and updates, ala Twitter. It was a great way to follow the figures you’re interested in without actually being friends with them. It eliminated the need for public figures to split their posts between their regular profile and their fan page out of privacy concerns. It was a pure value-add that enhanced users’ Facebook experience without taking anything away, and, most importantly, it gave us a way to connect with Myspace Tom all over again. (I really did miss him.)

This past Thursday, Facebook announced a “Subscribe Button” social plug-in for websites that lets readers subscribe to their favorite writers. That’s a cool idea—if I read a post that I really connect with, I’d be more than willing to give that blogger a shot in my News Feed with the simple click of a button. Again, it’s a pure value-add, and it provides a boost for bloggers, giving them another way to grow their personal brand and audience. Very cool.

 But if Facebook really wants to become a content engine, they need to take the Subscribe button one step farther and let people subscribe to websites, not just writers.

 I know what you’re thinking: “But what do you mean? Can’t you just “like” the fan page of whatever site you want to follow?” Yes, you can, but “like” and “subscribe” are very different things. Through Facebook’s EdgeRank algorithm, you’ll automatically see “most updates” of someone you subscribe to, while updates from a fan page are only seen by about 10% of fans on average. “Like” and “subscribe” signify very different degrees of interaction.

 For instance, I’m a social media dork, and I love Mashable.com. I’d love for as many Mashable updates to appear in my News Feed as possible. But the only way for me to get Mashable posts to appear in my News Feed often was to “;ike” Mashable, then wait for a Mashable post to actually appear in my News Feed, and then select “Highlight this story” when I saw the post. I had to do this 3 times before Mashable posts started appearing with the same frequency as subscribe.

 The problems? A) This is a pain in the ass, and B) most users don’t even know that the “Highlight this story” option exists.

 It could be that Facebook is avoiding offering the “Subscribe” button to websites in an attempt to convince websites to build Facebook social readers, which receive top-billing in the News Feed. But until Facebook offers a generous revenue-sharing model for the social readers, they need to offer websites a “Subscribe” button. If they’re really interested in being a user-friendly content engine, it’s a move they’ll make.