Read it. While the average post on news.YC is better than the average on reddit, there are many diamonds in the rough.

what app is it and what does it do?

It's called "360 Live", it lets you see your friends' Xbox 360 Live stats.

Some other notes:

  * single developer, aged 29, maintains separate day job
  * ratio of iPhone:Android sales is 3:1, but Android is unquestionably growing
  * his sales are ~90% US, ~10% UK
  * he very strongly prefers the Android dev environment
  * but he prefers the AppStore to the Marketplace
  * about 27% of Marketplace apps are "returned" (he suspects they're pirated)
  * on Android, copying an app to your SD card lets you refund but keep the app
  * he likes Java over Objective-C (but reiterates that it's a personal preference)
  * the back-end is written in .NET, which he works with full-time
  * best place for help on writing an app is Stack Overflow
  * the app got traction by being mentioned in a popular industry blog
  * he started the app on a hackintosh
  * evolved from personal hobby (gaming)
  * feedback and a lot of iteration were essential for a good application
  * personal phone is Nexus One
  * Apple's marketplace makes taxes easier
  * he has no plans to move to Window 7, Blackberry, or Nokia (no $ incentive)

My biggest take from it: when you have an industry that is very "tight" and hence easily targeted (gaming platforms, specific games, etc), making a great product into a successful product will require absolutely minimal marketing.