Advertising / Marketing:
American Marketing Association
The Direct Marketing Association
American Association of Advertising Agencies
Association of National Advertisers (represents 300 companies with 8000 brands that spend over $100 billion in marketing communications and advertising)
International Advertising Association
Incentive Marketing Association (IMA)
Point of Purchase Advertising International
MarketingProfs.com (marketing education & resources)
For Fun and Information:
National Capital Radio & Television Museum
NewsLink (links to media outlets in the U.S. and around the world)
Media:
Electronic Retailing Association (formerly the National Infomercial Marketing Association)
International Newspaper Marketing Association
Internet Marketing Association
National Association of Black Owned Broadcasters
National Association of Broadcasters
National Cable and Telecommunications Association
Newspaper Association of America
Outdoor Advertising Association of America
Television Bureau of Advertising
The Digital Marketing Association (Global, based in the United Kingdom)
Video Advertising Bureau (formerly Cabletelevision Advertising Bureau)