Something is amiss in the App Store right now. The best Twitter client, Tweetie 2 , is nowhere to be found. So where did it fly off to? Did Apple pull it for some violation? Unlikely. Instead, the app's new owners , Twitter, probably took it down. Why? Because their own version, dubbed "Twitter for iPhone," is likely about to be released. We see this happen all the time. For example, last week, the mobile payment startup Square was removed from the App Store just prior to the launch of its newly iPhone and iPad compatible app. Companies often remove their apps voluntarily to ensure the newest version is released when they choose. What this likely means is that Apple has already approved the new Twitter for iPhone, and now Twitter just has to put it in the store.