OpenWiki is a free encyclopedia that anyone can read, copy and edit. It is written collaboratively: there are no assigned authors, no editorial board and no approval queue. Someone notices that a page is wrong, or missing, or badly written, and fixes it.
Every page carries an Edit tab. Clicking it opens the wikitext of the page in a plain text box. You change what you like, describe your change in the edit summary, and save. The new version appears immediately.
No account is needed. Edits made without one are credited to Anonymous; registering a username reserves that name so that edits credited to it are demonstrably yours. See Special:ListUsers for the accounts that exist.
Nothing is ever overwritten. Each save creates a new revision, and every revision is kept forever in the page's history, along with who made it and when. Any two revisions can be compared side by side, and any old revision can be restored by copying it back over the current one. Vandalism and mistakes are reverted from the history.
OpenWiki aims to be an encyclopedia, which is a narrower thing than a general website:
<ref>...</ref>.Text on OpenWiki is available under the Creative Commons Attribution-ShareAlike licence. You may copy it, republish it, print it, sell it and modify it, provided that you credit the source and release your version under the same terms.
The gentlest way in is Special:WantedPages, which lists titles that existing articles link to but that nobody has written. Creating one of those pages fills a gap that somebody has already asked for. Help:Editing covers the markup, and OpenWiki:Community portal is where questions go.