Only a small percentage of users actively contribute to wikis, but these everyday people can make a huge difference to the readers, through constantly expanding and improving the wiki.
If you're really passionate about a topic, then you're the perfect candidate to become a wiki editor. Expressing your knowledge can help give back to the community and really make a difference to the lives of others.
It helps others
You probably know a lot more about a topic than you think, and contributing to a wiki helps others more to learn more about the topic... possibly even for generations to come. Your work could potentially be read by thousands or even millions of others.
Every little piece of knowledge helps... from finding out what special abilities that elusive game character has, to knowing how many pages each Harry Potter book contains. It means something to someone, and probably a lot more often than you think.
It can be rewarding
Each wiki needs constant love and care. From fixing typos to planning out whole new sections of content, it's a rewarding process when you can look back at what you've helped to build.
It's a fun, ongoing process
A wiki is never really complete, but with your help, we can get awfully close. You can make it part of your daily routine to come back and improve the wiki each day.