My 2 cents... As the parent of one of the new younger drivers in the Northeast region, prior to 11 months ago, I had never heard of Formula Vee. I had been involved in dirt track roundy round racing for quite a few years, but never really thought about SCCA road racing or ever looked into it. My son found Vees on his own last winter (via the inter-webs) and approached me telling me that this was something he wanted to do. The cost was one of the factors in HIS selection of this class along with the open wheeled aspect. After much debate, we pulled the trigger last January, bought a car and attended most of the NER events this past summer.
One of the ideas mentioned very early in this thread was mall/car shows. Back in the dirt track days, the local track used to hold an annual car show over the winter at one of the malls. They would fill the mall with cars from modifieds to street stocks. They were trying to fill seats, but its a good opportunity to get your "brand" in front of people, talk to the kids and parents and drum up some exposure (face to face).
IMO, social media is ok, but if your not already involved in racing, like racing, searching for racing stuff, I would think that gaining new drivers via this avenue alone is going to be difficult. I am somewhat contradicting my own experience with that statement, but my son was specifically searching for racing that he could get involved in, at a reasonable cost, and somewhere along the way he found FV. I think this was shortly after he saw the movie Rush.
I have to give props to the NER for holding the open wheel driving experience for vees this past season. Isn't that what the car dealerships are doing do when they let you take the car out for a test drive? Get them in the seat to convince them to make the purchase. If 2 of the ten drivers who participated end up with cars next year, a 20% return is not too hard to take. Following this type of event is where the social media stuff, youtube videos and websites kick in, so the participants can all show their friends what they drove last weekend the pass the word along.