Advertising is a hard problem that not many companies have solved at the scale of Twitter, that is what I am trying to get at. There are not too many social media networks out there which have hundreds of millions of users and billions of data points, and it's very misleading to say that work done in such a scenario is "something fairly well-understood and at any rate done by a lot of teams in a lot of places", when literally they're the only ones with Twitter type data outside of a couple of other Chinese social networks.