When we think of emerging local verticals, “green” is one of the most promising, as environmental concerns have pushed up the interest of consumers in having safe, healthy products that have minimal impact on the environment. MSN, Yahoo, Hearst and The Washington Post Co. have each developed “green” guides.

But green has a ways to go. Willem Maas, who founded the GreenHomeGuide in 2004 with local editions in the Bay Area, Los Angeles and New York City, says the “safe” and “healthy” part of it rings true. But the altruistic part of it doesn’t really. Green issues “motivate just a small segment of people,” he learned. “Health is more of a motivator.”

Up till now, Maas adds, green has had much more of an impact for commercial buildings than residential. “It is just getting up to speed now. I’ve been chastened by how much the buzz was ahead of the market.”

Maas initially envisioned his site as a cross between “a green Angie’s List and Yahoo Answers.” “What we did well with the GreenHomeGuide was using it for community, motivating people who have good answers, and to share what they know,” he adds. The site also did well via AdSense, where it had a high 3 percent to 5 percent clickthrough rate.

Ultimately, the GreenHomeGuide had a moderate level of success. But in August, Maas sold the site to the U.S. Green Building Council, a nonprofit that will be in a better position to leverage the site’s directory model, with nearly 60,000 LEED Accredited Professionals — an accreditation that’s growing 40 percent annually.

Hey, this is Kelsey Group Blog Post #500 for me. A nice milestone.