My arcade site gets about 400,000 unique visits per month and has 0 users. There's no registration, no community and no retention. The visitors that do come back to play games rarely click on ads and generate very little revenue statistically speaking. I've been toying with he idea of pouring lots of money on content and community features and converting some of these visitors into users. Of the 400K uniques I get 300K are all-time uniques. This means that I get to show whatever content I want to 300,000 new people every month. I suppose if I had top notch content and community features I could convert about 10% of these 300K and in a year I'll have 300K users. But... what's the value of these users? I keep seeing these start-ups who sell for $XXM dollars with 0 revenue because they have a stupid toolbar that controls windows media player with 12M users. I suppose if I had users, I could sell them as well. Maybe to one of the gambling/skill people (Playtech/888 etc...), but are they of any use to me? Sorry for the long post.
Make them register before they can play. Or have it coded so each user can only play 3 games without registering and after that they have to register.