Well, there are a variety of tournaments on this site. There is the Leagues, which are starting up right now, the Masters, which I'm in charge of (and are looking for reliable subs) and several gunboat tourneys out there. Each of these require several months of dedication to. Dropping out is highly frowned upon.
http://sites.google.com/site/phpdiplomacytournaments
Also, Ghost Ratings are done for everyone on the site starting after you complete a game and are done on a monthly basis. The Ghostmaker updates them, but he has been on a hiatus and they haven't been updated recently. That ranking system is similar to that of chess ranking systems. Each player, according to their points available (ghost points, not the ones next to your name, you start with 100) contributes 1/35th of their points (I think that's the right fraction) to the pot, and whoever wins takes all of them, and in draws they are split evenly. Thus if a highly ranked player draws with several lower ranked ones, he could go down in ranking. PPSC, World, and Ancient maps are weighed differently
Webdiplomacy Tournaments?
of GR. Say the other 6 players were my level (GR 135). Each of us would enter about 7.25 
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