Third Screen Media has signed MSNBC.com as a new publisher, and has added agency Universal McCann to its MADX mobile ad platform and network.

The MADX/Agency platform allows agencies to research, plan, buy, create, manage, deliver and measure mobile ad campaigns, ClickZ reports. The addition of MSNBC.com and Universal McCann could boost Third Screen's reported 50 million monthly impressions and bring more brand advertisers to the medium.

Other agencies already on board include MPG, Digitas, Starcom IP, Ogilvy, and Hill Holiday. On the sell side, MSNBC.com joins a list of fifty-plus publishers in TSM's mobile ad network, such as USA Today, MSN, TV Guide, CBS Sportsline, AccuWeather, WeatherBug, and Hollywood.com.

"We're looking to build a marketplace, getting the buy side and sell side together," Third Screen Media CMO Jeff Janer told ClickZ.