BuddyPress.org

@James: Thank you for your comment. Did I get it right, that your wikis are only in the backend? We want wikis on the frontend like blogs or groups.

@ostropunkt: PmWiki is really great. We have thought and discussed making group wikis? But our solution was, that wikis and groups are working in the same way.

You have a list of all your wikis on your profil.

You can have public and privat wikis.

And you can invite your friends to your wiki.