Internet Statistics
The Web sites listed below offer a variety of measurements of the Internet's size, traffic, and demographics. As with any information found on the Web, be sure to consider the source and methodology.
CyberAtlas
This service aggregates Internet statistics and news from a variety of sources. It includes information on market size, demographics, usage patterns, and more.
ZD Internet Magazine CyberStats
A monthly roundup of the latest in Internet market statistics.
Internet Domain Survey
The Internet Domain Survey seeks to map the size of the Internet by searching the Domain Name System. Updated quarterly.
Netcraft Web Server Survey
A monthly survey of what Web server software is used at the largest sites. Additional information about server software is available, and there's a nifty tool for identifying what software a particular site is running.
The 1997 American Internet User Survey
FIND/SVP presents graphically rich reports on Internet demographics, usage patterns, and other statistics. The Internet Timeline presents a possible scenario of the Internet's future.
Nua Internet Surveys
Nua offers a clearinghouse of Internet surveys from a wide variety of sources. New surveys are summarized and posted daily, or you can have them delivered to you automatically via e-mail. The site also offers charts and graphs of Internet statistics.
Open Market's Internet Index
A Harper's Index-like list of miscellaneous Internet statistics. You can also receive the index regularly via e-mail.
Internet Statistics: Growth and Usage of the Web and the Internet
This site hasn't been updated in a nearly a year, but it still gives an interesting historical look at Internet and Web growth since 1993.

Market Research
When you need something more authoritative and comprehensive than an executive summary, consult a market research company. Here's a list of companies providing research and analysis services for a fee. Many provide free summaries on their Web sites as well.
Computer Intelligence
Dataquest
FIND/SVP
Forrester Research
IntelliQuest
IntelliQuest's Zona Research
International Data Corporation
Jupiter Communications
O'Reilly & Associates Research
PC Meter
Nielsen Media Research