Community In Games
Since I can remember, Yahoo Games has had an active and consistent tournament schedule for nearly all of their multiplayer casual games. Players are encouraged to practice and earn rating points until they are ready to enter the tournaments. Yahoo keeps a complete list of tournament results for bragging rights etc. Player interaction consists only of traditional chat, and it is especially hard to keep to track of if you're talking with large game rooms of up to 200 people. Introducing avatars would make it easier for Yahoo Games players to remember and identify specific people within the community.
Because of the daily playing limit for Kingdom of Loathing, I did not get far enough to experience most of the social interaction mechanics of the game. I was able to try the very limited PvP, but did not make it to the chat, clan, or trade systems. The innovative part of KoL is also what limits it. Designed using barebones web technology, KoL cannot display multiple players or avatars on the map. Other than its technological limitations, Kingdom of Loathing provides a compelling community experience including a very active message board.
I'm curious to see if the final version of Puzzle Quest shows multiple avatars on the map. Although it is not built into the game, a clan structure will likely evolved as it does for all multiplayer RPGs. Given its casual emphasis and rock-solid single-player gameplay, Puzzle Quest does not appear to need any special event or tournament structure.