Twitter Groups: Popular Twitter Groups

Listed in order of popularity...
teachers
Journalists
Green Twitters
Aussies on Twitter
Healthcare
Bloggers
realestate
Photographers
Entrepreneurs
Public Relations
Etsy Merchants
Follow on Twitter
Top Conservatives on Twitter
Small Business Owners
seo
Artists
Wine - The Twitter Wine Community
Vancouver, Canada
Social media
Agile
OandAFanGroup
Ravelry
Musicians
Catholics on Twitter
travel
film, video, television editing and post production
elearning
Wedding Professionals
TwitterMoms
WordPress Users
Nonprofit Technology
Keleka's Friends @ Bonanzle
Homeschooling parents
Authors
Follow on LinkedIn
PHP Community
cartoonists
Follow on Facebook
Cloud Computing
Green Tweeple
Pro-Life
Toronto
SpeakerSite
Redesigning Journalism
Conservative Solutions
Vegans on Twitter
Virtual Assistants Community at Cagora
Drupal with Drupal Head
Writers who blog
Christian Women Tweet Up!
Advertising Agencies
DJs - Disc Jockeys - Party Rockers
Mommy Gossip—GNO
Green Thumb Gardening Group
Travel Junkies
marketing
ColdFusion
Hawaii
knitters
Tweet One Word
Gamers
Web Developers
Edubloggers
Museums
Virtualization
Theatre - uniting the global theatre community
Designers & Creatives
BlackBerry Addicts
Personal Development
1000 Markets
iPhone
LinkedIn Group
LDS
BlogSpot Users
Guild Wars
lesbians
Joomla!
FaceBook Group
AdobeGroups
Family History
Apple Distinguished Educators Worldwide
Buddhists
Lawyers
Flickr
Virtual Worlds
Dog Lovers
Top Conservatives On Twitter
Interior Design
construction
Knowledge Management (KM) Practitioners
Social Media Marketing
Consultants
Nonprofit Organizations
socialmediaclub
School Librarians International
science
Emergency Management
Book Lovers
Information Security
StumbleUpon Users
b2btweets - b2b lead gen, b2b marketing, more
Podcasters
Computer Geeks
Holistic Health & Wellness
Credit Union Fans
ChurchITRoundTable
International Speakers
Law & Technology
Music/MP3 Bloggers
Twitter Group: Illustration Lovers
Autism ~ Parents of Autistic Children
Twitter for Horse People
Svaz československých twitristů
Twitter Addicts
Photographers on Twitter
internationalschoolteachers
Space Enthusiasts
Houston Twitterites
Mommy Blogs
Public Media
Images4Education
Yoga
News from the middle east
Twitter WAHMs
Scottish Twitter Users Group
Twitter Birders
Geocaching
Health Care / Medical Professionals
Lawrence Twitter's
Absolute Write
TwitterDads
Finance
BlogHer Network
Complementary and Alternative Medicine
Email Marketing
Only Vegas People (true Vegans)
Voice Actors
illustrators
Google Certified Teachers
ChangeCamp
The Libertarian Twittosphere
Musicians
LifeChurch.tv
Follow on MySpace
NASCAR Fans
online_journalists
Medical Education
diabetes
Drum and Bass Worldwide
Cigars
Dave Matthews Band - Fans
Digg Users
Leadership
M300 Kelley School of Business Indiana University
cellityfriends
Atheism
Those Who Love The Game of Golf
Domainers
Music Industry Professionals
pastors
YouTube Users
Motorcycle Exchange Of Info and Chats
Master Data Management
Wedding Professionals
Columbus Tech Life
Austin
autism
Squidoo on Twitter
Book Marketing Online
Animal Loving Pet Parents
Pet Owners and Lovers
Linux
Atlanta Tweetup Group
The Classy Girls
SAP Community Network
Biotechnology -- business, science, and policy of the biotech in
TweetDeck Users
iPhone Application Favorites
Published Authors
Networking Divas
Girl Geek Dinners
businessintelligence
Ron Paul
the dawn and drew show
Meeting_Event_Planners
Twitting Christians
Law of Attraction
TwitterLawyer
PDX twitter
Ecademy Users
Moodlers
BLCK Twitters
Biotech and Pharmaceutical Tweets
Aviators
Desiring God
Creating Success Using EFT
The China Business Network
Pastor Tweeps
Interactive Multimedia Design
Nova Scotia Twitters
BookCrossers
eloqua
changebiz4better
Job Needed
UKTJPR @ MWC
Books and Reading
CigarTwits
Sports Industry Tweeters
Innovation catalysts
Food and Wine Lovers
Twurch
Storage folk (users and vendors) on Twitter
RecruitingBlogs
eBay Merchants
Integral
iabcinternational
openSUSE Community
SQL Server Twitter Group
maritime
asheville
Software Developers
freemasons
Black Writers
HRM Today: HR Bloggers
New Zealanders on Twitter
Bipolar Survivors
.NET Developers
Quilting with Moxie
Fantasy Fiction
Tweeps4Christ
iPhone Developers
Capgemini
Theory of Constraints on Twitter
Ignite Columbus
bibliotwit
Food bloggers
Tech Teachers k-12
Sound Engineers
Youth Marketing
Writers Who Blog About Writing
Students
New Orleans Tweeple
Neowin Group
WorldLanguagesTeaching
Bizniks
Feuerwehr
Pittsburgh Steelers Fans
Typical Shutterbug
Politics4All
Hamburger Twitterati
MindManager Users
NAWBO ~ National Association of Women Business Owners
ebay & Beyond: Basics to Business
MaineTweets
FriendFeed
Entertainment Business
golf
Mac Users
iranian
Head Hunters
American Mensa
Healthcare IT
Golf Fore Everyone
Cat Lovers
Wine PR
A Course In Miracles
SQL Heroes
Green Building Modern Design
PR Professors
PM - The Twitter Project Management Community
Gardeners of the World
Twitter-Santamützen-Weltkrekord
Parents of Twins and Multiples
SF/F Book Reviewers
The eLearning Guild Annual Gathering 2009
Stuttgart
Nutrition
Breast Cancer Awareness
Translators
Sodexo Careers
Biotechnology
AdWords
Screenwriters Coast to Coast
Birmingham City Uni media students
hiking
Nurses
Animal Lovers
Commercial Real Estate Investors
Accidental Entrepreneurs
Business Bloggers
Western, Mass
Meeting and Event Planners
mobilesforchange
M312 Kelley School of Business at Indiana University
Work At Home Dads
Home Stagers Learn Home Staging
Blogging 4 Boomers (Blogging, SEO, List Building, Social Media a
2009 Great Backyard Bird Count
funwithfoodstorage
Frugal Shoppers
Professional Organizers
librarians
Firefighters / EMT
Dallas Cowboys Fans
University of Warwick
bdsm-de
Toastmasters
New Homes Professional Network
Feminist Blogizens
esperanto
Albuquerque
Pro-Life Canadians
Beer: A Twitter Group for serious beer tasters
Semantic Web