BusinessOrganizations, Companies, Blogs and Websites on Twitter.

Companies & Organizations

• CASS Central Arizona Shelter Services, the largest capacity homeless shelter in Arizona.
• Chattanooga Market - Chattanooga's largest community market & art festival
• City of Casa Grande Library, Casa Grande, AZ USA - reading recommendations with links to its online catalog
• Health Care For All - a state-based, non-profit consumer health care advocacy organization in Massachusetts.
• Innocent Smoothies (lovely UK drinks company, innocent drinks)
• Los Angeles Fire Department
• Make - MAKE Magazine
• MARTÍN SOTELO® Consultores y Abogados - Full-service law firm, based in Madrid, Spain - Homepage - MinorCelebrities
• Marvel - comics, movies and games (See summary article)
• Oriental Trading Company
• Babel Media - Game testing company, uses Twitter to recruit new games testers
• San Francisco Zoo 
• STAR-TIDES - a research effort to encourage information sharing and develop Communities of Interest to support populations in stressed environments
• Wiltshire and Swindon Archives - list of historic documents currently being used (details here)
• WUW The Webcash_Universocial_Web - Free personal webcashmotor's register & delivery
• Gool-Bama-Cash - Finantial recipe to upgrade the Classic Economy into 4G3W
• Public Citizen - A national, nonprofit citizen advocacy organization that fights for health, safety and democracy.

Software

• Adobe Flex
• BMC Software
• Drupal
• Firefox - web browser
• Netscape - web browser
• Opera - web browser
• Oracle
• Plone - content management system
• WordPress - blogging software

Blogs

• A Healthy Blog
• Bloggers Blog
• I Can Has Cheezburger? - LOLcats blog, ICHC
• Nerd Beach - Interesting Things Washed up from the Cyber Sea Nerdbeach.com 
• Linking money by Mousephone 4G3W - Datevaluation's upgrade for the Classic Economy 
• SocialEarth - social entrepreneurship news

Arts Organizations (Theatres, Dance Companies, Museums, etc.)

• Repertory Theatre of St. Louis - Missouri's most-honored live, professional theatre 

Websites, Social Networks, and Web Applications

• 30Boxes - 30boxes.com
• Bookring Directory - connected to BookCrossing.com
• deviantART - deviantart.com
• DemystifyingDigital.com - Dan Havlik and Maryan Pelland tweeting
• Flickr - flickr.com
• Mininova - Mininova.org, torrent site
• Monster - monster.com
• Media Temple - mediatemple.net 
• OnMyList - onmylist.com
• PBWiki - pbwiki.com
• Ravelry - Knitting resource and networking site, Ravelry.com
• Technorati - technorati.com
• URL Tea - urltea.com
• Woot! - woot.com

Twitter Applications

• SnapTweet - Flickr/Twitter mashup
• TweetUps
• Twitterdildonics 
• Twit4 Directory - Find schools, companies and organizations using twitter.

Religious

Buddhism

• TricycleMag - Tricycle Magazine
• ForestHermitage - Wat Pah Santidhamma; Warwickshire, UK
• Longquansi - Longquan Monastery; China
• LYWA - Lama Yeshe Wisdom Archive

Christianity

Islam

Judaism

Unsorted (these should be sorted!)

• Adaptive Path
• American Astronautical Society
• Appropriate Infrastructure Development Group
• Apollo Apps
• Adegga Social Wine Shopping
• areyouwatchingthis.com (RUWT?)
• Ars Technica
• A Word a Day
• Beatenetworks
• Blip.tv
• booktweets
• Bucketworks
• Capgemini
• Center Networks
• Citizen Space
• CocoaLabs
• Corkd
• Coworking
• Craft Magazine
• Dishola
• Dogster
• Don Quijote Spanish Schools Worldwide
• Download Squad
• ETS Talk
• eHub
• exModia - exmodia.blogspot.com
• Gamers Game
• Global Protection Corporation
• Goplan
• Hackszine
• HowToWeb
• HypeDiss
• Ideacodes
• Imified
• iStalkr
• Joyent
• Kiva
• Laughing Squid
• LifestyleRadio.ca - Your Alternative Lifestyle Station
• Live Earth
• LOL nptech
• MacSB
• MacZOT
• Ma.gnolia
• MarketWatch
• MeeVee
• Microformats
• mkefood
• Modelfolios
• Mosio
• Nabaztag
• Naughty America
• NifNaks - twitter of felted wool crafter and owner of NifNaks.com
• PicoCool
• Planned Parenthood
• Photojojo
• PodcastPeople
• PostCrossing - international postcard swapping/tracking site
• qarrtsiluni - online literary magazine
• Rete Civica dell'Alto Adige
• Rogue Amoeba
• Sandbridge Technologies - fabless semiconductor company
• Satisfaction
• Sevenload
• Shopping Blog
• Six Apart
• Social Media Club
• SocialText
• soziety, language learning social network
• Stikkit
• Sub Pop Records
• Techmeme
• The Home Depot
• The Naughty American - Official Academic Journal of Naughty America
• TUAW
• Tupalo
• Veer
• Watchers Watch
• Web414
• Web608
• Web715
• WHATWG
• WikiAnswers
• winetweets
• WriteNews
• QYPE
• Jeff Rense Headlines
• Think Like A Genius