Wiki      -       means quick in Hawaiian.
Wikis have been around since the mid 1990s, but only recently has the general public become aware of their existence.  Some of the more popular Wikipedia entries have been edited hundreds of times by dozens of people. 
Some Wikis are open to everyone.  This can become problematic when spammers or malicious people vandalize entries, but they are usually quickly fixed by concerned members of the wiki community.

It can be difficult for people to get used to the idea of a website that anyone is allowed to add to or edit.  The notion of private property is so deeply embedded in our society that it's difficult to imagine going into someone else's webstie and changing things, even when we are invited to.

Many libraries have been working to make themselves a physical hub of the community.  With community programming and useful workshops, libraries have attracted people to library who may otherwise have never visited.