Facebook's "Discover New Games" algorithm is broken. Sometimes it accurately shows what games your friends have recently played. Other times, it references a game they used to play a long time ago and have since stopped. Furthermore, there are times when Facebook appears to be outright lying.
Here's the scenario I'm seeing the most often: Facebook claims one or more of my friends plays a given game. I ask them about it. They don't play it anymore or have never heard of it before. I ask them to send me a screenshot of their installed apps on Facebook. The game in question is not listed.
You can try this yourself. Login to Facebook and head over to facebook.com/games. On the right-hand side you'll see a "Discover New Games" module that randomly generates games you should check out, based on popularity and what your friends supposedly play. It 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.
You can hit refresh as many times as you want to see new recommendations. You can check what apps and games you have installed (or ask your friends to check what they have) by navigating to facebook.com/settings?tab=applications (Drop down menu in the top right => Account Settings => Apps).
The games in question are typically quite popular. Here's a list of all the games that Facebook has recommended to me, because my friends apparently play them: Bejeweled Blitz, CityVille, CSI: Crime City, Empires & Allies, FarmVille, Games on Mindjolt, It Girl, Nyanicorn, Restaurant City, Sorority Life, Texas HoldEm Poker, and Words With Friends. Some of these recommendations make sense given how popular the games are and who supposedly plays them, but others simply didn't add up.
One friend I called supposedly plays Restaurant City and Sorority Life on Facebook. She told me she used to play Restaurant City a long time ago but has since uninstalled it. As for Sorority Life, she's never heard of it. I asked her to check if she has either of them installed, thinking that maybe the former got installed somehow by accident. Nope, neither of the two was listed in her apps.
Facebook said another friend plays Games on Mindjolt and Texas HoldEm Poker. When I contacted him on Facebook Messenger, he told me he uninstalled the former a few weeks ago since people kept sending him chip requests. As for the latter, he says he hasn't played it for over a year. I asked him to send me a screenshot of his installed apps without uninstalling anything. He has nine apps installed. None of them are games.
Last but not least, Facebook informed me one of my friends plays CityVille. He said he's never played it before, nor has he heard of it. When I asked him to check, he was very surprised it was installed. He also noted he had an app request from a friend who plays CityVille. My friend uninstalled it, but that didn't change the fact that Facebook had already recommended the game to me even though he never played it, and that it still was recommending it to me even after he uninstalled it.
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.
To help mitigate this, Facebook started testing the "Discover New Games" module back in March 2011. Facebook's hope is that users will try new games if their friends are already playing them. This is based on trust: if your friends play a game, maybe it's actually a good game worth trying? Unfortunately, Facebook is breaking with that trust, since I cannot tell if my friends really are playing a given game. Have they played it recently, did they try once or twice a long time ago, or as I've discovered, have they never played the game at all, let alone heard of it?
I first heard about this issue earlier this month from The Bulldog Estate. I finally got around to checking up on it again when one of my Facebook friends jokingly teased another because of a game that she supposedly played.
I've talked to many friends over the last few weeks about the Facebook games they play and how this compares to what they and I see in the Discover New Games module. Even if Facebook starts only recommending games that your friends have actually played at some point, this isn't enough. Many of the friends I contacted did indeed play the games that were mentioned, but they haven't done so for months, or even longer. Some of these friends have uninstalled them, but others just never got around to it. Others still have the games installed but aren't really sure how that happened (it was likely through an app request from a friend), and haven't ever played the game.
It's possible that Facebook users simply don't remember games that they accidentally installed at some point (and maybe even quickly uninstalled). This is why some say they have never heard of a given game. Nevertheless, I think Facebook should only be recommending games that your friends are currently playing, not ones that were just installed at some point in the past.
I have contacted Facebook about this issue and will update you if I hear back.