I've used the TestFlight digital testing and distribution system for mobile apps a few times, both as an end-user (when companies want to send me their apps to try out), and as a developer (when I've passed an app I'm working on to someone else for testing). Apple's app distribution and provisioning system can be tough to figure out, but TestFlight makes it all much easier, with a very snazzy web interface, and the ability to install a preview app on a non-jailbroken device with just a few taps on the screen.
Now, TestFlight is becoming even more useful for developers on all platforms, as the service has announced compatibility with Android phones. You might argue that doesn't affect us here on the iOS side of the fence, but it does show just how big TestFlight has gotten. The company has announced that it's hosting more than 300,000 iOS apps already, with one-third of those uploaded in just the past 90 days.
Its client base expands beyond independent developers. TestFlight tells TUAW it has hosted builds for big companies like Adobe, Disney, Spotify and Tumblr.
We occasionally heard rumors that Apple might want to buy TestFlight, considering how great the company is at distributing mobile apps. I'm not sure if this Android announcement helps or hurts that line of thinking. On the one hand, Apple might want to pick up TestFlight just to keep the service iOS exclusive, but of course any experience on Android would become generally useless if an acquisition does happen.
I think TestFlight will stay where it is. The service is very helpful and seems to be booming, so it seems unlikely that Apple will swoop in and acquire it for the official app ecosystem.