Snopes has been targeted as one of them. It seems for half a year now the company has been pushing Zango, formerly 180Solutions, onto people visiting the site in one form or another. Zango, whose own (former) employees don't have anything good to say about it, has been spotted more than once peddling their wares in shady ways. So much so that the FTC saw it fit to levy a huge fine on the company. So why would Snopes, a site that has gained a considerable amount of fame for interesting factoids in dispelling or confirming urban legends, want to associate with these folks?
Money is one reason, though third party association is another. Regardless, it seems Snopes is very well aware that they are divvying up ads for Zango. I suppose someone has to, else where would Zango get the money to pay their millions in fines the next time the FTC comes after them.