Everyone can change everything!
A wiki is not just a static page. It is like a big document that everyone can add, change and delete things to. This has developed to a very powerful tool that you can write and change!
en.wikipedia.org
The big free encyclopedia. Thousands of articles about everything
en.wiktionary.org
Dictionary and thesaurus. The goal is to have an explanation of every english word and to translate it to every language on earth.
species.wikimedia.org
The goal is to catalogue all species on earth with an description, what family it belong to and their latin name.
en.wikibooks.org
A collection of free, open-content textbooks
en.wikibooks.org/wiki/Wikijunior
The aim of this project is to produce a series of books for children aged 8 to 11
en.wikibooks.org/wiki/Cookbook
A collection of all kind of recipes.
en.wikisource.org
A collection of free content source texts built by its contributors.
en.wikinews.org
Free-content news source.