Twitter on Tuesday unveiled a new advertising program that delivers promoted videos to the tweet stream of users of the popular messaging platform. The new program adds to the source of advertising revenue for Twitter, which has struggled to convince investors it is on a path to profitability. By using Promoted Video, its easy for brands to upload and distribute video on Twitter, and to measure the reach and effectiveness of this content, product manager David Regan said in a blog post. Regan said that to make it easier for advertisers, Twitter will offer a cost per view model: This means advertisers only get charged when a users starts playing the video, he said.