Idea for a Web App

All of my experience writing web apps have been to learn or test an idea, or something that I decided wasn’t such a great idea after all. For a long time I’ve wanted to come up with something useful enough to want to publish, but simple enough that I thought I could get it done in a reasonable timeframe as my first project. I think I’ve thought of something.

Neither Xbox Live, Nintendo Miiverse, or PlayStation Network gives you a way to find your Twitter/Facebook friends. What I’m thinking of doing is making a site (probably using Django) which lets you login with Twitter and/or Facebook, enter what someone would need to find you on any of those gaming networks, and then use that information to find your friends who’ve done the same on the site.

I’m imagining that as far as web apps go, this is a pretty simple one. In my mind it’s just social login, a form to enter your Xbox/Miiverse/PSN usernames, some API calls to get your friend lists, and some database queries to match it up to users of the site. Am I missing anything here?