Facebook serves 3 billion Like buttons a day

Facebook is serving three billion Like buttons a day, up threefold from when the company launched the product across the web in April, according to Ethan Beard, who runs Facebook’s Developer Network. On top of that, the company’s social plug-ins are now on 350,000 sites, up from 200,000 almost a month ago and 100,000 in May.

Like buttons form the backbone of Facebook’s powerful recommendation engine. They feed into ad targeting, help virally distribute content and apps among hundreds of millions of users, and allow the company to hone its search engine and news feed algorithm.

For comparison, Tweetmeme’s retweet buttons, which have been around for at least a year longer, were being displayed 500 million times a day and were on 200,000 sites as of last month. If Twitter doesn’t make an aggressive push to help market the U.K.-based company’s content-sharing buttons, it’s hard to see how either will be able to keep up with Facebook’s momentum.