It seems they have really started getting into contacting people regarding promoting business on Facebook. They sometimes send out promotions to get people to advertise on the site so you may even see that again soon. As for now, if you're really interested in promoting your business, just contact customer service and they will certainly be more than willing to help get you started with promoting on their site.
I must say, you would be in front of millions of people going the Facebook route. I think it's a great idea.