Strange new spam attack on News.YC

We've had a rash of spam submissions in the last 24 hours. All the sites have links to something called Entrecard (http://entrecard.com). Looks like some strange combination of MLM and SEO. Anyone have any idea what's going on? Was it just that someone mentioned this site as a good place to spam on their forums, or is there some central organization controlling this?

In any case, for now we're killing any site that has any reference to Entrecard on it, even if it's conceivably on topic.