Stats for Webreference.com are also available.

Internet Statistics

CyberAtlas (*)

Internet market research and information site. Provides a periodic overview of Internet trends, demographics, marketing, and advertising information.

CyberGeography

Interesting collection of experiments and approaches in visualizing internet statistics and topology.

GVU WWW User Surveys

User surveys dating back to 1994. The surveys feature a wide variety of WWW usage and opinion-oriented questions.

The Internet Index

"An occasional collection of facts and statistics about the Internet and related activities." By Win Treese of Open Market.

ISC: Internet Domain Survey

Estimates the number of hosts and domains by doing a complete search of the Domain Name System. From the Internet Software Consortium.

comScore Media Metrix

Web market research information and analysis service providing demographic data, measuring Internet and digital media audiences and usage since 1996.

MIDS: Matrix Information and Directory Services

MIDS provides statistics on about the Internet and estimates of its growth. Information is presented textually, graphically, and in geographic maps.

Netcraft

Conducts the Web Server Survey which tracks the usage of HTTP server software. Also offers a searchable hostname database.

Nielsen Net-Ratings

Online usage and popularity statistics.

Nua's Internet Surveys

An organized collection of Internet statistical surveys. Has digests of the important research reports and demographic surveys from the major research companies. Includes summary graphs and data of Internet statistics and trends. Offers a monthly newsletter.

StatMarket

In-depth statistics on a wide variety of Internet topics, and a sharp interface. StatMarket provides free global Internet usage statistics gathered from tens of thousands of web sites and and millions of daily visitors.

TheCounter.com

Detailed browser statistics, including information on monitor resolution, color depth and java/javascript usage.

Yahoo: Statistics and Demographics

Yahoo's collection of related sites.