If you are a Twitter user, you are already familiar with Promoted Tweets, which is Twitter’s fancy name for “ads”. Now, the official Android Twitter app will bring these promotions to your timeline:
Promoted Tweets will appear in your timeline like any other Tweet, and like regular Tweets, they will appear in your timeline just once; as you scroll, the Promoted Tweet will flow with the rest of the Tweets in your timeline.
The promoted tweets were already accessible in the timeline of desktop and mobile versions of Twitter, but had only appeared in searches in the official Android app. Recent updates to the app had added “Promoted Accounts” suggestions in your “Who to Follow” section. In the coming weeks, the app will show promoted tweets in your timeline from brands or companies that you are currently following.
If you feel that the promoted tweet isn’t relevant (or you think it’s just plain annoying) you can remove it from your timeline with a single swipe.
For now, it appears this will not apply to third-party Twitter Android apps.
source: Twitter blog