What's a Wiki?issue.gif

A wiki is a web site that lets any visitor become a participant: you can create or edit the actual site contents without any special technical knowledge or tools. All you need is a computer with an Internet connection. A wiki is continuously “under revision.” It is a living collaboration whose purpose is the sharing of the creative process and product by many. One famous example is Wiki-pedia, an online encyclopedia with no “authors” but millions of contributors and editors. The word "wiki" comes from Hawaiian language, meaning "quick" or "fast."

The Difference between a Wiki and a Blog (from a chat with Adam F. of wikispaces at Tappedin.org)

The simple answer is that a blog is like a journal. It's great if you want to have an ongoing dialogue or discussion. Say, if the kids are keeping a daily diary about their homework, or about any topic.
A wiki, however, is less about new content every day, and more about evolving the same content over time.
So for example, on a wiki, you could have a student post an essay, and then another student can make some additions and corrections, and another, and another, and over time the essay improves and becomes the work of the whole class.
Blogs are about communicating, wikis are about getting work done, or working together

Inviting and adding people (and students!) to your WIKI!
Each person you invite will get an email with a link, when they click it, they will be asked to create an account, and they will automatically be made a member of your space But what if you want to invite students without email addresses?
In that case, all you have to do is send us (help@wikispaces.com) a list of usernames and passwords, and we can create all of your accounts for you. You can then just tell the students what their username and password is and show them how to login

All about using Wiki's in the classroom: online chats from tappedin.org...