Let's look at the aspects of a good campaign wiki. You can see an example side-bar off to the side of this post.
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Instead, I suggest PBWorks. It's free, easy to use, and very, very flexible. It will require a few more minutes of set-up (they obviously don't provide you with character sheets), but once you get the format you like, making changes is very easy.
I require my players to keep their up-to-date on the wiki. This has a number of bonuses. It allows me to audit player extremely easily, and without making anybody feel uneasy. It allows me to put them up against enemies that they may find fun and interesting. It allows me to see who is under equipped, and provide them with some nice loot in the next adventure. It allows me to quickly review a character's backstory.
It also allows other players to look at each other. This encourages fun group dynamics and teamwork, as well as minimizing player overlap. Most of all, as with every page on the wiki, it gets players to the wiki and thinking about the campaign between sessions.
After every session, I write up what happened in an Adventure Log. I tend to run fairly intricate games, so reminding the players what has happened is crucial. Make sure to give individual characters credit for what they do. Players love reliving glorious or dangerous moments.
Dividing up group loot can be difficult for some groups. Clarifying exactly what's what often helps. A group loot page should not only list the items that are up for grabs, but also have a comments section for players to discuss who should get what.
The Character Chat is perhaps the most important part of a wiki. This is where players can have in-character discussions in between sessions. The Character Chat is a fun and exciting place for your players to be engaged in the game when they are not actually playing. It keeps enthusiasm up and is a great opportunity for roleplaying.
If you are running a homebrew game, then you probably want to tell your players about the world. This is a section for you to explain everything that you players should know, from geography to religion to NPCs of note.
Of course, you should feel free to write up anything else you like on your wiki. I lay out my House Rules on the wiki, so everything is clear with the players. I keep track of crafting on my wiki, as it tends to get rather complicated. I also keep track of real world information – for example, who paid for dinner a particular night.