Twitter’s timeline is currently overrun with ads for some users, in what at first appeared to be a glitch involving the distribution of Promoted Tweets. Typically, a Promoted Tweet — which is just a regular tweet an advertiser has paid to promote more broadly — will appear just once at the top of a user’s timeline, then scroll through the timeline like any other tweet. Now, however, Promoted Tweets are popping up with increased frequency. Some users report seeing them as often as every four to six tweets, in fact. Others are reporting seeing the same Promoted Tweet more than once.