A decent percent of people are voluntarily paying for it right now, enough that it is already profitable at about a 10:1 ratio of profit vs cost of operation. The platform can grow quite a lot without expenses going up since my main expense is just server power, and I am not using much of that at all right now.

I think I have engineered it all to scale well, and I don't anticipate costs increasing. The plan right now is to not run ads, and to make almost all features free for all users in perpetuity.