This might be true in NAm. In other parts of the earth, it might be different. There are different cultural barriers and different things which are considered "normal" for meeting new people. I'm sure "dating" sites are working on ways to integrate this feature into their offering. Or, let's say, find 5 other people around me who want to play some 3 on 3 basketball, or a squash partner, whatever.
>Coupon / Daily deals
Again, true in the US market. Other markets might be ripe for a newcomer. For example, a team in SAfrica could develop something to fit the local market.
>Online Dating Sites.
Sites, yes. But there's still room for innovation. It's far from perfect.
>Book Exchanges for colleges
True. Will there be any physical books in the long run anyway?
>Apps that create Apps
Ok.