Dan Martell's Flowtown got shut down because Facebook didn't like the fact that they were selling private data of users (I got this from http://www.youtube.com/watch?v=a7eLPcSJIog).
I've built www.whiqq.com which lets people search publicly available posts from Facebook fan pages only. But what people or businesses actually want to search is public posts from people's profile to generate leads and not just the Fan pages. I know Facebook policy does not allow that and it does not allow to build search engine using Facebook data. But companies like www.buzznumbershq.com and http://www.brandwatch.com/ are doing this.
- Should I build it anyway ? Because I know I can do a better job and provide better analytics!!
- Should I not work on a product that requires me to search with Facebook data ?
- Why are companies like buzznumbershq and brandwatch still indexing Facebook data ?
If you are uncomfortable about using Facebook Data but still inspired to index public data to help customers generate leads - then I would decouple the essence of your goal from the detail of how.
My recommendation is to create something like a plug-in or stand-alone utility that works off it's own (separate) data file. Then create simple interface files that extracts that data from various utilities like Facebook, LinkedIn, twitter, <future yet to be created next big deal media app>, and transfers/converts it into your proprietary database.
I feel you may be creating an imaginary dependency between your goal and facebood data.
Call me if you want to flush this idea out more.
I would avoid anything to do with Facebook at this point. The network is consumed with spam and low level engagement. Have an app? Google Apps or Apple are the way to go.