KnowThis.com

Below KnowThis.com presents links to sites that each contain a listing of many academic and professional trade organizations.  Where possible an effort is made to classify the primary focus of each site's listing.

Professional Listings & Searchable Directories

• American Society of Association Executives *While the organization running the site is primarily an association for those in the association business, they do offer a searchable database called Gateway to Associations for locating trade associations (presumably member’s sites). Can filter by U.S. state, country and keyword.  While not nearly as in-depth as other sources it is FREE!
• Associations on the Net - Internet Public Library *Searchable database of hundreds of associations that maintain web sites.  
• Directory of Associations *This site claims a database of over 34,000 associations, however, must pay a fairly steep fee to access.
• Encyclopedia of Associations *This publication is generally considered the leader in listing trade associations world-wide and currently contains information on over 100,000 non-profit associations. Can also be found in an online version called Associations Unlimited.  However, the publication is very expensive and access is best obtained through a university library or possibly through one of the major online databases listed in the Resources for Tutorial found under the Data Collection: High-Cost Secondary Research tutorial.
• Federation of International Trade Associations *Information on over 450 international trade associations, however, requires registration (free) of email using email address to access search and other features on the site.
• Trade Association Forum *UK site that offers searchable directory locating trade associations.

Academic Listings

• Academic Marketing Associations *Includes listing of non-U.S. based associations. From Paul Driessen.

Promotion and Sales

• PR Associations *Listing of international, national and local (mostly US) PR and PR-related groups.
• Sales/Incentives/Promotion Associations *List of those associations dealing with incentives and promotions.  From Incentive Magazine.

Marketing Research

• ESOMAR's List of International MR Associations *Contains an extensive international listing of associations though the search function is a little limited.
• Quirk's List of MR Associations *International listing of marketing research associations and organizations.

Transportation & Distribution

• Journal of Commerce - Trade Associations *Lists links to shipping and international trade associations.

Others

• Call Center Associations *Listing of associations and groups that have some connection (this is a stretch for some that are listed!) with the call center or CRM market. From CallCenterDepot