There's almost no selling going on on the website, so probably most of their business spreads through word-of-mouth, with visitors to the site already having been referred by happy clients. They also probably need to control how many new clients they adopt to ensure they have adequate capacity before scaling.
Hey, I remember you from poker! Glad to see you're doing well. I'm assuming zerocater's just for companies in SF at the moment, not someplace nearby like Burlingame?
