Word-of-mouth and search engines, apparently. We posted one game on Digg back in the summer, had a flurry of hits and then about 6 (yeah, I'm not leaving off a digit) uniques a day for the next 3 months. But traffic has grown steadily since late October, and we haven't been doing anything. No Google ads, no promotional postings, not even telling anyone other than linking it in our social-network profiles and answering family friends who ask "What are you up to these days?" We're at about 1000 uniques (73,000 hits) for the month of February so far.

I'm kinda amazed that we even have users, given the quality of the product that we've got up there and the lack of updates in the past 6 months.