https://techcrunch.com/2017/10/24/twitter-advertising-transparency/

Twitter is responding to political scrutiny over the role it may have played in spreading Russian misinformation, and to a bipartisan Congressional bill proposing new regulations for online ads, with some new initiatives of its own.

So it’s launching an Advertising Transparency Center where users should be able to see all the ads running on Twitter, the content/creative of those ads, how long they’ve been running and which ones are targeted specifically at you. Anyone can then report an ad as inappropriate or simply say that they don’t like it.