Facebook has started testing a new sidebar module that shows you what games your friends are playing. "Discover New Games" is a small box that shows up on the right-hand side of a user's Facebook page, in the same area where you might otherwise see the "People You May Know" module, according to Inside Facebook.
The new box displays the full name and profile picture of friends who are playing a game you haven't installed yet. The name of the game, its thumbnail icon, and a "Play Now" link appear below the list of friends. Facebook is hoping that users will try new games that their friends are already playing in the same fashion they find new friends on the social network.
Facebook used to publish game activity directly to the user's News Feed so that all friends could see them. In September 2010, however, the site changed this functionality so that game updates were only shown to people who already play a given game. This significantly reduced the number of new users trying the game.
The change was in response to many people blocking certain applications after being annoyed by constant updates in their News Feed. At the same time, Facebook lost a big way of promoting games, so now it's trying something less intrusive that will still bring in more gamers. The new module should help developers who are trying to market their games on the social network, but it likely won't be as "successful" for stimulating growth rates as the previous method.