Mobile ads -- and their formats -- are adjusting as different kinds of screens proliferate and marketers move beyond standard banners to discover different ways to engage consumers. Changes in mobile usage, such as the rise of mobile video, are spurring advertisers to experiment with different ad types. "We are doing more and more rich media ads, but we think it's still an untapped market. Whether you're leveraging GPS functionality in maps or calendar functionality, you can do so much with the phones from a rich media perspective," said Brian Colbert, vice president of mobile advertising sales for Pandora.