About 90% are on a free account, most others on a paid account through StackCommerce or similar tools.

Monetization is my next goal - and probably should have been much earlier. I'm thinking about 1 month free trials automatically converting people to a paid account after that. I would ask for their creditcard details during sign up. I'm still trying to figure out what would be the best approach.

More on that in my next post, How I Make $50 Million A Day Without Working.