It may be the most embarrassing branding error since GM found out that the Chevy Nova meant “no go” in Latin America.

And it’s a reminder of what happens when clueless people try to use Web 2.0 language because they think it’s cool but have no idea what it means.

Last week, the National Organization for Marriage, a conservative organization opposed to gay marriage, launched a new $1.5 million “Two Million for Marriage” initiative that it dubbed “2M4M,” evidently in an effort to appeal to younger, web-savvy people. (For those of you who are interested, PR Place has the scoop on activist Maggie Gallagher, who is behind this group and a related “Institute.”)

NOM also launched Facebook, MySpace and Twitter accounts, urging supporters to “use those networks and invite your friends.”

Sounds like a great, up-to-date way to launch a grassroots – or, as skeptics would say, “AstroTurf” campaign, right?

Except that as anyone knows who has spent five minutes online, M4W and M4M have acquired specific meanings, and 2M4M means two men looking for, let’s say, company.

The ridicule has gone viral, from the blog of former New Republic editor Andrew Sullivan (who helpfully suggested the group consult the Urban Dictionary before naming their next initiative) to the Huffington Post, which posted a hilarious video that’s safe for office viewing. Another blog, Box Turtle Bulletin, guessed that “Maggie Gallagher’s PR advisor must hate her.”

Perhaps worse for NOM, a pro-gay marriage group managed to seize the www.2M4M.org web site. And if you go to http://twitter.com/2m4m, you get the pro-gay-marriage group, not NOM.

Maybe NOM was smart enough to foresee all this and figured it was a way to get lots of extra publicity. If so, my hat’s off to Ms. Gallagher and whoever is advising her.

But it’s more likely they were just cluelessly trying to be cool and got caught, er, with their pants down.

Don’t let it happen to you.