If you signed up without a Facebook account the great features of the app wouldn't work without a lot of effort on the users part. For example it takes all 700

If you signed up without a Facebook account the great features of the app wouldn't work without a lot of effort on the users part. For example it takes all 700 of my Facebook likes, matches them against others, and shows our commons likes (interests). It also shows friends in common and allows me to easily update my pictures (the only pictures I have of myself are ones I've been tagged in on Facebook). You could create a non-Facebook system but I don't think many people would use it and without significant work inputting interests etc. they wouldn't get very good matches.