Digital Sidebar, which yesterday unveiled its Sidebar mobile ad platform that uses the "white space" on a mobile phone screen before and after calls and SMS messages, already has some big-name clients.

Mobile Marketer reports that both Paramount and Universal Studios have signed on to use the new ad-serving platform. The start-up also has agreements with Hasbro's Trivial Pursuit, Paige Premium Denim, Universal Motown and a large credit card company.

"When I devised this platform, the whole idea behind it was to create a new form of media, since people were just starting to talk about mobile," Digital Sidebar founder and CEO Stephanie Grossman said in the article. "I was hearing, 'Nobody knows the right way to do it,' and I thought, 'Hmm I think I do.'"

Sounds like several advertisers already agree with her.