A-Z5

second life
The game second life is a 3-D virtual gaming site where players can build and own an entire world.

http://secondlife.com/

seti@home
"SETI@home is a scientific experiment that uses Internet-connected computers in the Search for Extraterrestrial Intelligence (SETI). You can participate by running a free program that downloads and analyzes radio telescope data."

http://setiathome.berkeley.edu/

smartmobs.com
"A website and weblog about topics and issues discussed in Howard Rheingold's book Smart Mobs: The Next Social Revolution."

http://www.smartmobs.com

sourceforge.net
he world's largest software development site. It provides free hosting to open source software development projects. It has 100,000 projects and over a 1000,000 registered members.

http://sourceforge.net/index.php

stray cinema
Stray cinema is an online community where you are able to download and re-edit the raw footage from a film we have shot in London. This will provide people from all over the world with an opportunity to create their own version of the film."

http://www.straycinema.com

Technorati
A blog website in which members can share, and comment on media politics, music, etc.

http://www.technorati.com

Tera-Grid
"TeraGrid is an open scientific discovery infrastructure combining leadership class resources at nine partner sites to create an integrated, persistent computational resource."

http://www.teragrid.org

The Co-intelligence institute
It "works to further the understanding and development of co-intelligence. It focuses on catalyzing co-intelligence in the realms of politics, governance and cultural evolution. We research, network, advocate, and help organize leading-edge experiments and conversations in order to weave what is possible into new, wiser forms of civilization."

http://www.co-intelligence.org/

WEB 2.0
Tim O'Reilly "re-emphasizes the most important points of this development, talks about the evolutionary relationship between open & free and shares his vision of bionic systems that combine human and computational intelligence"

http://www.openbusiness.cc/category/partners-feature/

Whole Earth 'Lectronic Link' (WELL)
WELL is a "Pioneering online community known for engaging conversation and intelligent debate, and it features more than 260 conferences".

http://www.well.com

Wikia
Wikia are wiki communities creating free content with the MediaWiki software. These are hosted for free by Wikia, Inc., the company which runs the project. Jimmy Wales and Angela Beesley launched Wikia in 2004 to provide community-based wikis inspired by the model of Wikipedia.

http://www.wikia.com/

Wikibooks project
Wikibooks is a collection of free content textbooks that you can edit, and it has a sister company called "Project". http://en.wikibooks.org/wiki/Main_Page

Wikipedia
Wikipedia is a multilingual free content encyclopaedia, which is built collaboratively, and has over two million articles.

http://www.wikipedia.org/

WordPress
A semantic personal publishing platform with a focus on aesthetics, web standards, and usability."

http://wordpress.org/

Writely
A "collaborative word processor that lives on the web, not on your desktop; you access it through the your browser and save documents on the Internet." Meaning you can edit the document from anywhere with Internet access.

http://google-d-s.blogspot.com/

Ycombinator
A venture firm that funds early stage business startups. It invests in software and websites.

http://www.ycombinator.com

Youth Noise
A website which is non-profit, and "affiliated with Save the Children Federation. It provides teens with a forum to express themselves and take action."

http://www.youthnoise.com