Facebook's No. 2 App Is a Surprise Trailing Farmville is ... Microsoft's Live Messenger By Nick McMaster, Newser Staff Posted Nov 10, 2010 3:23 PM CST 0 comments Comments Windows Live Messenger is the second most popular app on Facebook. (Microsoft) (Newser) – The main finding of a recent survey of Facebook apps is not at all surprising: FarmVille remains the most popular application, with more than 16 million users logging in daily to tend their virtual crops. Plenty of other games populate the top 10. The occupant of the No. 2 slot, however, is a lot more interesting: It's Microsoft's app for Windows Live Messenger, with 9 million users, ReadWriteWeb reports. Having failed to touch the Google search hegemony, Microsoft seems to be hoping it can gain a foothold in social networking services. The first step in achieving that is integrating its Messenger community into the dominant social network, which is exactly what the latest version of Messenger does. Even more striking is that, to avoid performance issues, Microsoft has been taking the integration slowly, and currently offers it to only 20% of Messenger users. If that ratio held up after full integration (unlikely), it would give Messenger about 45 million daily Facebook users. Take that, Zynga.