What are the top Twitter apps on the iPhone? It's hard to say because the iTunes store doesn't have a Twitter category (Twitter apps are lumped in under "Social Networking). But AppsFire , the iPhone app sharing service, might have an answer—at least for the early adopter crowd who tend to use AppsFire (i.e. people like you, dear reader). AppsFire looks at apps actually downloaded and kept on people's iPhones. Based on a sample of 1,500 AppsFire members, the top ten Twitter apps on the iPhone are: TechCrunch50 Conference 2009 : September 14-15, 2009, San Francisco