This time last year, we were reporting Rufus Griscom, the mind behind sex-with-a-brain site Nerve.com, was expanding beyond his latest spin-off (parenting site Babble.com) with an environmental blog. And then … nothing. Realizing we went nearly a year without seeing Griscom launch his green title, we revisited the issue in August, where Griscom told us "our research indicated that the green advertising category is inadequately mature so we put it on ice … We will launch it at some point, but only when the advertising base is there." Might Griscom have been wiser, then, than the treehugging webtrepreneurs attempting the same thing?

The evidence says yes. While Griscom held off on launching a new eco site, others already in the space have seen their niche tank.

Last year, MSN and Yahoo debuted their green "channels." Ad agencies like Burst Media unveiled green mini-networks. Washingtonpost.Newsweek Interactive launched Sprig.com. Hearst put out something called The Daily Green. And Treehugger.com, one of the original independent green blogs, got bought by Discovery Communications. Meanwhile, "healthy living" site Lime.com was sold off.

And where do they all stand today? In pretty miserable company. Relays Mediaweek:

Initially, it appears as though the portals have scored the most success, with the 10-month old MSN Green approaching about 1million uniques, per Nielsen Online. Yahoo Green eclipsed 3.8 million users this past June according to Nielsen—though inexplicably, its traffic has recently tanked. Meanwhile, Sprig has yet to register with either researchers, while The Daily Green reached an anemic 200,000 uniques in August, according to comScore. Since its sale, Lime’s audience has dived below Nielsen’s reporting minimum.

Adam Seymour, vp, director of strategic communications at Optimedia, expects the category may be due for a shakeout. “It’s difficult for these sites to really get the audiences they need and the premiums they want to charge,” he said. “A lot of these sites are really tiny. It depends on how niche a client wants to go.”

But on the plus side:

Still, most sites in the category claim steady audience growth and continued advertiser interest. For example, Yahoo Green has run campaigns for The Home Depot, Sharp and Pur Water, while MSN Green has spending from Toyota, Honda and Procter & Gamble.

Not surprising, no one inside the category believes that the bloom is off the green garden.

“We have grown steadily in terms of traffic and turned the corner dramatically this year,” said Sam Silverstein, editor of Yahoo Green. “This is definitely not a fleeting cause.”

Lisa Tiedt, director of MSN Green, said that the site’s audience has doubled this year. Still, she said that what initially drew Americans to the eco-movement has shifted. “The conversation has evolved,” said Tiedt, adding that two distinct audience segments have emerged: the more hard-core, altruism-driven “dark green” users and a much larger base of “medium green” mainstream users.

Of course, it helps that Yahoo and MSN can basically dump reams of traffic from their homepage and other sub-sections into their green channels, and boost their readerships. Not unethical, just a ridiculous advantage that, say, Nerve/Babble's Griscom doesn't have. So perhaps it makes sense that he's avoided the space, at least for now, while the existing players battle it out for ad dollars.

So, by Nerve's business acumen, it is better to stay in the business of viral loops: sex (Nerve.com) begets babies (Babble.com) begets ad dollars.