Wiki
On a wiki, people can write pages by collaboration. Pages are watched closely to see whether changes are good or bad. If one person writes something wrong, another can correct it. Other users can also add something new to the page. Because of this, the page gets better when people change it. Administrators can block someone from editing if they vandalize, or for other reasons. Users can also discuss things on wikis. Discussion can help people understand things better and get a chance to tell their views. In Wikipedia the talk pages are for that, but in some wikis, the article and the discussion are in the same page.