MySpace was bought for exactly that reason. It has a large enough number of returning monthly visitors (accessing archived photos and what not) for that data to

MySpace was bought for exactly that reason. It has a large enough number of returning monthly visitors (accessing archived photos and what not) for that data to be valuable to the adtech vendor that bought it. If you're looking to acquire lots and lots of customer data, there are far cheaper ways to go about it than trying to build your own social network from scratch.