Ted from Kik. Just wanted to jump in and answer a few questions:
On October 21, 2010 we launched a completely new service. The only thing that was the same between new Kik and old Kik was the name and the app store accounts. Users from the old system (about 55K active in the last week before the hard switch over) were notified that the new service was available and that the old one would soon be shut down. About 23K did get the upgrade, but almost all of them dropped it immediately due to losing all of their contacts from the old system, and the now lack of built in SMS texting. You can see this in the graphs - a brief peak, followed by a multi day flat line. I really apologize if this is misleading, it was not intentional.
The numbers. They are real. We can hardly believe it ourselves. The app is built to be incredibly viral (more on that later), but we never spam any of your contacts. All that happens is on registration, we do a quick one time, secure scan to let you know who on Kik you might know. That's it. Nothing is ever stored or shared, and nobody outside Kik will ever hear even a peep that you have joined Kik (unless, of course, you tell them, which a lot of people seem to be doing!) From there, people keep using it because they really like it. It is a bit hard to understand or explain (well, not as hard as Twitter I guess, but still) so it is probably best to just use the app for a bit. You will see why people like it.
We are moving as fast as possible to scale the servers, and add features. As noted below, we've been working on our vision for almost two years now, and this is just the first step. Expect some pretty cool things to come, and until then, thank you for letting us share in this incredible ride.
Ted