Post Master Direct  
   Offers online direct marketers a large network of high-quality, targeted opt-in email addresses on the Internet.
   http://www.postmasterdirect.com/

YesMail  
   Offers targeted opt-in direct email marketing through campaign building, tracking and list management services.
   http://www.yesmail.com

MeMail  
   Free email publications delivered directly to your email inbox. News, entertainment, health and fitness, business and financial, and lifestyle.
   http://www.memail.com/

Opt-Influence  
   Supplies opt-in email newsletter services
   http://www.opt-influence.com/

Opt-Email  
   Offers targeted Opt-In based Email Marketing
   http://www.opt-email.com/

Prospect Mail  
   Provides opt-in email address lists of opportunity seekers or entrepreneurs.
   http://www.prospectmail.com/

EmailPro  
   United Kingdom based company offering full service opt-in email marketing services and web site promotions.
   http://www.emailpro.co.uk/

Permission Direct  
   Provides opt-in email direct marketing services.
   http://www.permissiondirect.com

BlanketMail  
   Opt-in email direct marketing company offering list rental services with advanced targeting and full statistical tracking
   http://www.blanketmail.com/

Direct Qlick  
   Opt-in email list management, brokerage, broadcast, and tracking services.
   http://www.directqlick.com

TKL Interactive  
   Provides opt-in email lists, copywriting, and campaign management services directly to marketing and advertising professionals and agencies.
   http://www.tklinteractive.com

MetaResponse Group  
   Offers permission based e-mail and direct marketing services including list brokerage and management, e-mail and direct mail lists.
   http://www.metaresponse.com

Email Maestro  
   Ethical permission based opt-in email marketing company, with over 18 million opt-in subscribers.
   http://www.emailmaestro.com/

411 iServices  
   A provider of targeted business and consumer opt-in email marketing lists and email addresses appending to postal mailing lists.
   http://www.411iservices.com/

EmailFactory  
   Viral and relationship marketing services for businesses and organizations.
   http://www.emailfactory.com/

Mailtrack  
   A UK based e-mail marketing company, specializing in opt-in email lists and CRM email delivery software.
   http://www.mailtrack.com/

North American Mailing Associates  
   Provides opt-in email marketing lists and email addresses appending to postal addresses. Fresh sources of B2B and B2C opt-in email lists.
   http://www.namalists.com

Satori Software  
   Home of Bulk Mailer Plus and MailRoom ToolKit, an address management and postal mailing solution that is compliant with the USPS, Royal Mail and Canada Post.
   http://www.satorisoftware.com/

List-Business  
   A list of companies that provide opt-in direct email services.
   http://list-business.com/opt-in-list-systems/

eMail Lists  
   An online email marketing solution that enables businesses to build, send and track permission-based opt-in email marketing campaigns.
   http://www.emailists.com/

5StarMedia  
   Offers online direct response marketing including email transmission services, and opt-in email lists for rent.
   http://5starmedia.com/

Charlwood eMarketing  
   Online direct response agency specializing in customer relationship management(CRM) solutions, permission email marketing, online contests, email newsletters and promotions.
   http://www.charlwood.com/

iEntry  
   Free, professionally written newsletters on a variety of topics that go out to millions of opt-in subscribers per month.
   http://www.ientry.com/

List Advertising  
   A guide to opt-in email list advertising and marketing resources for advertisers, list owners, managers, and editors.
   http://www.list-advertising.com/

Opt In Inc.  
   Provides permission-based email marketing services to the online direct marketing community.
   http://www.optininc.com/

market1der  
   Offers design and implementation of opt-in email marketing promotions as well as cd-rom business cards and HTML designed letterheads for email.
   http://www.market1der.com/

eLeads Marketing, Inc.  
   Opt-In lists for industries including mortgage, life insurance, automobile sales and warranty, debt consolidation, and business opportunity.
   http://www.leadleader.com/

I-Behavior, Inc.  
   A cooperative, transactional history database containing consumer buying behavior profiles contributed by member catalog, publishing, and e-tailer companies.
   http://www.i-behavior.com/

Armadillo Online Marketing  
   Specializes in opt-in email lists, and related services.
   http://www.armadilloemail.com/

Digital Cement  
   Helps companies design, write, and evaluate the effectiveness of E-mail and web site content.
   http://www.digitalcement.com/

Blue Ink Solutions  
   Email marketing specialists providing clients with email strategy development, campaign management, opt-in list rental and vendor selection services.
   http://www.blueinksolutions.com/

Manic Mailer  
   Permission based UK marketing application firm specializing in developing, managing, and communicating with customers through email with html templates, and real time reporting.
   http://www.manicmailer.com/

Cannon Data-Systems, Inc.  
   An online email list broker that supplies double opt-in addresses and offers tracking and campaign management.
   http://www.emailmarketingnet.com/

Wall Street List  
   A double opt-in email marketing, list management, brokerage, and delivery service provider.
   http://wallstreetlist.com/