We will be slowly expanding out, definitely in the works for some of the larger cities to be launched. A national launch is a a couple of months away still.
Great article, it is definitely the approach that makes sense for most start ups, people can spend time developing and then not meet the problem they were trying to solve.
The tough part is getting users to be a part of that feedback loop, but as others have said it helps you answer that "how do I get users" much quicker.