In September we introduced Subscribe to make it easier for people who want to share their public updates with more than just friends to build an audience of subscribers. Today we’re launching the Subscribe button for websites, a social plugin any site can add to give visitors the option to subscribe to contributors in one click.
The Subscribe button for websites works just like the button on Facebook; once clicked the user will begin seeing the public posts of the person they have subscribed to in his or her News Feed. The subscribe action is also shared -- allowing others to subscribe directly via the News Feed stories, and further increasing viral distribution.
Similar to the Like button, the Subscribe button can be easily added using XFBML or an iframe. Here's the XFBML button for Mark Zuckerberg's profile:
<fb:subscribe href="https://www.facebook.com/zuck" width="450"></fb:subscribe>
For HTML5-compliant markup:
<div class="fb-subscribe" data-href="https://www.facebook.com/zuck" data-width="450"> </div>
And the iframe version:
<iframe src="https://www.facebook.com/plugins/subscribe.php? href=https%3A%2F%2Fwww.facebook.com%2Fzuck &width=450&appId=APP_ID" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:450px;" allowTransparency="true"> </iframe>
The Subscribe button is already live on Absolute Radio, AllThingsD, ANSA.it, The Daily Beast / Newsweek, Forbes.com, GQ Italia, The Huffington Post, Mashable, Ministry of Sound, msnbc.com, NME.Com, TechCrunch, TIME.com, TODAY.com, and washingtonpost.com (see examples here). We look forward to seeing it on many more sites in the coming weeks.
Tips and best practices are available here. More information, including a code generator to instantly create a button for your site, is available in the Subscribe Button documentation.