Twitter ad platform was always coming... but hashtag ads? Even if these are just a temporary work around I get the distinct feeling that Twitter are going for

Twitter ad platform was always coming... but hashtag ads? Even if these are just a temporary work around I get the distinct feeling that Twitter are going for very much hyper-targeted advertising. In lots of ways if they are this is much better than just "sticking adSense on", which so many web sites opt for. But I guess when you have the time, as Twitter do, you do it right.