Facebook will introduce a universal “Like” button that Web publishers will be able to put on their pages. Similar to the Facebook “Share” buttons that are already popular with many Web sites, the “Like” buttons will make it easier for Web publishers to offer more social experiences, in essence allowing Facebook friends to enjoy those sites together. While “Share” buttons allow users to post links that their friends see on their Facebook pages, those links are fleeting. The Like button will allow Facebook to keep a record of what a user linked to, providing the company with ever more data about people’s preferences. Facebook, in turn, plans to share that data with Web publishers, so that a magazine Web site, for instance, may be able to show users all the articles that their friends like. A site like Yelp may show reviews from a user’s friends, rather than those from strangers. – from NYTimes