Giving developers an environment they can play with and build great products around is the best way of achieving success.

Let's not forget that Twitter would have never been that successful without its developer community. If you can attract developers to rstat.us, then you will probably attract more users over time.

But that developer community is a given if you are making a competitive or alternative service to something like Twitter. It's a prerequisite, not a bonus. I would argue you're still not giving the users enough of a bone.