I agree with gman314, and I wonder if the current system shouldn't be improved. If I'm not wrong, I believe that now a player, who's just signed up the site, can join 2 games. If he doesn't miss any (of the 2) starting phases, he can join a 3rd game. After 6 phases there are no more restrictions, so maybe it takes a couple of days.
This system's goal is to prevent curious people, who maybe don't even know the game, to join too many games right after the sign-up and then disappear because they're not really interested in Diplomacy, or because they are but they realized this site speaks a language they don't. For this purpose it works perfectly.
But, looking at DL's stats, I wonder if it couldn't be improved making the steps a bit longer for newcomers. Many of them are like children who get tired of a new toy after a week or two. Perhaps there's a way we can do it without discourage honest people willing to play properly.
We'd have 2 advantages:
1) Give to newcomers the time to understand how this site works, esp the Reliability Rating thing. If it took 2 or 3 weeks before they could join an infinite number of games, we'd have so much less NMRs in our games and so much less newcomers destroying their RR.
2) People with a low RR would try to recover their RR instead of just open a new (limited) account.