Video-calling is starting to be used by more and more people. It has real benefits and now we have the platforms and infrastructure in place to do it almost flawlessly. But there still aren't that many video-calling apps that work across iPhone and Android. And even though there have been a couple, like Fring or Qik, the quality of the video streams hasn't been that great.
Tango changed that and it offers great quality video calling on Wi-Fi, 3G, and even 4G. Because it's so good and free, people have shared it with each other and it has managed to get 1 million downloads in only 10 days. That's very impressive for a new start-up. They offer support for most popular phones, but I hope they can bring support to more in the future.
That being said, I'm sure video-calling will arrive to GTalk in Android Gingerbread. I just hope that it's highly integrated with the OS and easy to use. Basically, I don't want to feel like I'm using an app, but like I'm using something that is built-in the OS.