At the same time, they have not done anything to reduce certain types of spam, such as the repeated reply chains under the President's tweets, which can so easily be identified as spam by the fact that they are unrelated to the parent, and appear in the same order under a number of parent tweets.
It's a total mess.
Added: I went back to find an example of the spam chains to reply to Srslyjosh, but I'm pleasantly surprised that they seem to have finally eliminated them. I withdraw that specific criticism I guess.