ok fair enough...
Wikipedia itself runs on software called Mediawiki.
It's the one that we use for the wiki bit of the DIY FAQ. Normally at wiki.diyfaq.org.uk, but currently you can see some of it on the wayback machine:
Links to content hosted on it are posted here frequently - so it's likely you may have used it perhaps without even realising it.
The main advantage is that it supports multiple users and editors. So anyone can upload new stuff, or make corrections or additions to existing stuff. You don't have to wait for the FAQ maintainer to pull his finger out to make changes!
Editing it requires no web based coding knowledge - so if you see a typo, you click "edit" and fix it, then save the result. You can also look at the history or any page and see all previous revisions and what changed between them. You can use it to host images and then post links here.