What is a wiki?
A wiki is a collection of shared webpages that can be edited by anyone in the community, which could be a group of staff and students (UCL Wiki) or the whole world (as is the case of Wikipedia).

How do I use a wiki?
Every page in a wiki can be edited. You simply enter the edit mode (generally accessed by clicking on a link or button) and edit the page you were currently viewing. Special syntax to format your text or to add links to other pages or websites.

As wikis can be edited by anyone, the pages are open to attack by users wishing to vandalise the pages. Wikipedia have some guidelines for preventing vandalism (Wikipedia).

Can I add a wiki to my Moodle course?
Yes, Moodle allows you to add wikis in every course. Moodle uses it sown Wiki tool that is separate from this wiki. You can always link to  a wiki.ucl.ac.uk hosted wiki from your Moodle course.