Search Engine Watch 
Search Engine Watch is the authoritative guide to search engine marketing and search engine optimization.

Marketing Sherpa 
Excellent resource that publishes useful news, case studies, and best practices data about internet and integrated marketing.

ClickZ 
ClickZ has expert advice about Internet marketing, email, brand & interactive marketing, and search engine marketing. Read the latest Internet advertising news, market research, Internet statistics and more.

Emarketer 
eMarketer publishes Internet market research, statistics and objective analysis on Internet marketing, Internet advertising, online trends and online demographics

IAB
The IAB evaluates and recommends standards and practices, fields interactive effectiveness research, and educates the advertising industry about interactive advertising.

Leichtman Research 
Leichtman Research Group offers actionable research on the adoption and impact of broadband, media and entertainment products & services.

Nielsen Online
Nielsen Online specializes in online audience measurement, including syndicated, customized media and market research to assist companies to understand their competition, and their audience. Custom reports available.

Email Experience Council 
Professional organization that strives to enhance the image of email marketing and communications. Resources, initiatives and standards, events, and news.

PEW Internet 
The Pew Internet & American Life Project explores the impact of the Internet on children, families, communities, the work place, schools, health care and civic/political life. The Project aims to be an authoritative source for timely information on the Internet's growth and societal impact, through research that is scrupulously impartial.