Kevin Systrom announced the milestone achievement today at Techcrunch Disrupt Beijing. During the talk, Systrom also revealed that there are now 100,000 downloads of their app per week in China alone. Impressive to say the least.
The intersection of exquisitely-crafted native apps with ubiquitous networking and cloud-backed storage. Think about an app like Instagram. It's totally about the native experience -- smooth scrolling, fast access to the camera, instantly-applied image filters. But it would be completely uninteresting if not for its server-backed social networking. Used to be that native apps felt best but anchored your data to the device, and web apps running in a browser offered you ubiquitous access to your data but had a crummy front-end experience. We're getting to a point now where you don't have to compromise.