It’s been several months now since Greystripe was acquired by ValueClick, and the results are showing, according to Greystripe General Manager Michael Chang.

Greystripe says that since launching its mobile video ad format earlier this year, it’s seen an increasing number of brand advertisers flock to video. So many, in fact, that Greystripe already has seen a 300 percent increase in the number of campaigns booked thus far in the fourth quarter relative to all of the prior quarter.

Universal Pictures and its agency, Ignited, ran a campaign with Greystripe to drive trailer views and promote the theatrical release of “The Change-Up,” which is now available on DVD and Blu-Ray. The two-week campaign, targeting men 18-34, generated nearly 900,000 complete trailer views. (Greystripe doesn’t collect personally identifiable information, but it surveys consumers to get age and gender on an opt-in basis.)

Chang says end-users  have the option to skip Greystripe video ads at any time. Yet on average, consumers have watched an entire video ad 50 percent of the time, with click-through rates of between 1 and 3 percent.

Chang credits ValueClick’s acquisition of Greystripe in April of this year as a big reason the company has been able to grow so fast. San Francisco-based Greystripe has since doubled its staff, now up to about 65, and opened offices in Seattle, Phoenix, Minneapolis and Atlanta.

Those markets are home to some of the big brands that Greystripe works with, as well as second-tier markets where regional franchises, like auto dealers, are adding mobile to their advertising mix. In October, Greystripe launched its Ad Boosters, a component of which enables local retailers to offer Find Store, Coupon and Buy Now buttons that serve to prompt a specific action on the part of the consumer.