After Joanna Shields announced at LeWeb that Facebook would deliver a new social plugin for websites that would allow Facebook users to subscribe to user updates on websites, the company has made it available for developers and website users to utilise.

The Subscribe button for websites is very similar to Twitter’s Follow button and operates the same way as it does on Facebook’s own website. If a website has embedded the button and a user clicks, they will instantly begin receiving updates from that brand or person in their News Feed.

Facebook has also incorporated it into the shared stories, meaning that if a new post is shared in your stream, they will be able to subscribe directly via that News Feed story, increasing the virality of the post across Facebook.

Screen Shot 2011 12 08 at 18.44.16 Facebook rolls out its new Subscribe button for websites

To embed the button, website owners have three options; a XFBML code snippet (one using Facebook’s own markup and another that is HTML5 compliant) and an iFrame.

To embed a Subscribe button on your website, hit the Subscribe Button widget page to generate your own.

The Subscribe button has been embedded on a number of websites already, including 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.

With Twitter delivering a huge update today, the battle to generate interactions on the two services has gone up another few notches.