Twitter on Monday announced that users will soon begin seeing Promoted Accounts in their mobile timelines.
Promoted Accounts, introduced in 2010, are a way for advertisers to get their Twitter feeds in front of more users. On desktop, they have appeared as "who to follow" recommendations. Though the ads have run in a dedicated space above "Trends" on desktop, on mobile they will appear in the timeline, à la Promoted Tweets:

Twitter has been running a beta program with a few businesses for the new ad unit and is satisfied enough with the results to take it global, Tarun Jain, product manager of revenue, wrote in a blog post on Monday.
The announcement is the latest of Twitter's attempt to monetize users' activity. Other introductions this year include expanded photos in the timeline (which could better display ads), pre-roll ads for video and Amplify, a program that lets TV networks run sponsored video-enabled tweets in the timeline.
Images, Twitter, Getty/Bethany Clark