I'm one of the engineers at Openfolio focusing mainly on the iOS app. We're really excited about our launch, and we're all around to answer any questions about the app or Openfolio as a whole.
I wrote a lot of the backend/API at Openfolio. We put together a blog post with a little bit about our stack, and challenges if anyone is interested: <a href="http://code.openfolio.com/post/96462395197/openfolios-stack" rel="nofollow">http://code.openfolio.com/post/96462395197/openfolios-stack</a>