Users do use the phone based Market app than Facebook for Android, but that is expected considering that you have to use Android Market even to download the Facebook app. Neilson analyzed the usage data from its proprietary device meters on the smartphones of the thousands of consumers who agreed to be part of this Analytics research over the 30 days of September.
Even if game downloads topped the app categories in the recently released dissection of 10 billion app downloads from Market by Google, the actual usage patterns shows that top ten used apps are dominated by actual apps not games. Games like Angry Birds and Words with Friends were the only ones to grab the last two spots in top ten, and that is only limited to 18-24 age category, in rest of categories, Angry Birds in the only game in top ten.
