Wikipedia:Why on Earth would I want to contribute to a wiki

There are many good reasons to be involved in Wikipedia:

It is a self-governing mechanism that creates positive externalities
It's fun.
It's educational.
It's social.
You are part of an exciting development making use of the open source idea.
You can correct other people on the spot without asking their permission!
It's dynamic. Wikipedia has created more than a million articles in five years.
It's interesting to share your knowledge with other people, particularly knowing that others can instantly edit or react to what you've written.
To contribute is to gain.
Did we mention, it's fun.
Ultimately it's yours.