I really like the concept of it, but I can't give feedback here on the app because I don't have an iPhone.
I think initially people will be excited to play contests against one another, but the issue I've dealt with in the past is: (a) someone starts winning massively and the contest becomes stale or (b) there's too many contests, and the community is spread out too thinly.
I think initially people will be excited to play contests against one another, but the issue I've dealt with in the past is: (a) someone starts winning massively and the contest becomes stale or (b) there's too many contests, and the community is spread out too thinly.