Mochi Media is announcing today that it has named a new chief executive, George Garrick, who will take over the Flash game advertising company from founder Jameson Hsu.

Hsu will remain at the San Francisco company as its evangelist and product overseer under the title “chief Mochi.” Hsu will continue to talk with game developers, publishers and advertisers about collaboration with Mochi Media.

Garrick has a background in online advertising as the former CEO of Flycast Communications, a direct-response online ad network that he led through an IPO in 2000 and subsequent sale to CMGI for more than $2 billion.

“We’re at the point in our growth where we want to step it up,” Hsu said. “George has the kind of experience that I don’t.”

Hsu said it was a tough decision to step aside but that it’s good for the company’s future. He said that MochiAds now reach more than 70 million unique users a month through web-based Flash games that use Mochi Media’s ad-serving technology. The catalog of Mochi games is now more than 5,000. Hsu said the company was drawing more ads from overseas thanks to a partnership with Google, which recently launched the AdSense for Games game ad technology.

A lot of web sites are discovering that games are sticky, keeping users coming back and sticking around on a site longer than they otherwise might. Mochi Media is kind of an arms dealer, providing white-labeled games to any site that wants them. And those games are free to play because Mochi Media puts video ads into convenient loading scenes or between game levels.

Mochi Media got started in 2005 and launched MochiAds, its flagship game distribution and ad network, in October, 2007. The company inserts small video ads into the Flash games that can run on any web browser. It tracks exactly how many times the games get played and on which web sites. It can thus collect ad revenue and pay the developers their share. That has helped a vibrant community of Flash game developers who have enough revenues to develop more online games.

Since it can track games wherever they are played, Mochi Media has helped developers monetize games that were previously being pirated. Web portals such as MSN Games can improve their audience engagement by putting widgets on their sites where visitors can play the white labeled games from Mochi’s network of thousands of game developers.

The business model is similar to the one used by NeoEdge Networks, which has an ad platform for more complex downloadable games. But Hsu said Adobe’s improvements to Flash have made higher-quality games possible on any web browser, since Flash’s penetration of the web browser market is near universal.

Garrick joins other recent Mochi Media hires, including Eric Boyd, former vice president of platform engineering at Yahoo, and Carol Werner, former vice president of sales at MySpace.

Mochi Media raised $10 million in venture funds this summer and so it doesn’t need cash at the moment. Garrick said in an interview that was one of the attractions of the job. He said his task will be to grow sales even more dramatically. Altogether, Mochi Media has raised $14 million in funding. It has 29 employees.