I've thought the same with the rest of them too (an exception of youtube because of ad revenue potential, even though they still operated at a loss for something like a decade).

Facebook is the same question, and seeing the stock value soaring (up front) when, as best I could tell, the stock value should move comparable to an ad agency. Since that's the only apparent revenue.

Luckily, we've learned better and now know that it's because they soak up all information they can on everyone and package it and sell it to every bidder.