Yahoo buys video ad firm BrightRoll as rumours surface of plot to oust CEO Marissa Mayer

Yahoo makes another acquisition, but top shareholders are said to be exploring the possibility of a merger with AOL

Yahoo has purchased video advertising platform BrightRoll in a deal worth $640m (£402m). The acquisition continues the web firm's strategy to boost revenue from mobile and social platforms, and comes only months after it purchased an app analytics startup Flurry in July.

Brightroll describes itself as "the industry's leading programmatic video advertising platform", enabling "advertisers to reach four in five viewers online". The acquisition is expected to be completed at the beginning of 2015.

Welcoming the deal, Yahoo CEO Marissa Mayer said:

"Video, along with mobile, social, and native, is driving a surge in digital advertising. Here at Yahoo, video is one of the largest growth opportunities, and BrightRoll is a terrific, strategic and financially compelling fit for our video advertising business," she said.

"This acquisition will accelerate the growth of both companies - we can help BrightRoll scale to even more advertisers globally and they can bring their tremendous platform offering to Yahoo's advertisers.

"The combination builds positive momentum for Yahoo's broader display advertising business in 2015," she added.

Tod Sacerdoti, CEO and founder of BrightRoll, also welcomed the deal, stating: "We believe the next step for programmatic video advertising as an industry is to extend and standardise globally, make cross-device buying simple and measurable, and complement and integrate with TV.

"We are excited to join Yahoo to materially advance efforts in each of these areas. We're still in the early innings as an industry, and together, BrightRoll and Yahoo are committed to the vision of helping grow the entire video advertising ecosystem," he added.

However, according to a report by Reuters, all is not well at Yahoo with some top shareholders said to be so unhappy with the way Mayer is running the company that they've made a request to AOL CEO Tim Armstrong to look into the possibility of a merger and running a combined Yahoo and AOL operation.

The rumours of a plan to oust Mayer come after Yahoo revenues slipped throughout the course of this year.

At least two top-10 Yahoo shareholders are thought to be so unhappy with Mayer that they're willing to approach Armstrong, who has previously acknowledged the benefits of such a deal. However, the AOL CEO has played down the possibility that a takeover will actually occur.