L.A.’s established online ad rep firm Gorilla Nation is betting that there’s advertising life beyond the top 50 kids sites for marketers looking to expand their internet reach. The agency’s new division GNKids launched today with the express purpose of becoming a vertical market aggregator of mid-tail web properties – in other words the company is repping immersive ad opportunities on sites that host traffic of between one million and 15 million unique visitors per month. Kyle Fletcher, who worked at portal Kidzworld.com for the past six years, is heading up the North American operation HQ’d in Vancouver, Canada as VP of ad sales.

Millsberry.com and Kidzworld.com are already onboard as anchor clients. Millsberry, operated by food giant General Mills, is a lively online virtual world that has three million unique visitors per month who spend an average of 41 minutes per day on the site. And starting next month, thanks to GNKids the site will sport third-party advertising for the first time. Fletcher, for his part, is moving upcoming marketing efforts beyond the standard banners and pop-ups that populate the top 50 kids sites in the US. He’s looking at creating fully integrated branding opportunities that engage kid users. To that end, Fletcher’s currently setting up an in-house creative and design team to provide clients with a one-stop shopping experience.

Check out KidScreen‘s upcoming Nov/Dec issue for more details on GNKids startup plans and partnerships.