Sites with good general information on site development. SEO tools, site testers, validation services, site statistics, site rankings, backlink reports, etc.
Any Browser Campaign
Information on building web sites that are accessible regardless of browser, platform, handicap, connection or other factors to produce a more accessible web.
Domain Name Details
DNDetails.com provides a free service to look up a large amount of information on a domain or IP,
including IP, Server type, WHOIS, page design info, a thumbnail of the site and much more.
Paydirt Design LLC
Paydirt Design is a web development and design company based out of Butte, Montana. Our goal is the success of your web presence; helping to develop your brand on-line and grow your business. We strive to bring this through all of our interactions with you, and any work we do for your web site.
Search Engine Positioning
How to improve the positioning of your site on the major search engines, without it taking over your life.
Search Engine Watch
Search Engine Watch provides tips and information about searching the web, analysis of the search engine industry and help to site owners trying to improve their ability to be found in search engines.
SpyFu lets you see which keywords your competitors are buying and which ones they optimize their site for. Once you understand the competition, you can beat them at their own game or you can exploit their weaknesses.
W3C CSS Validation Service
A free service that checks Cascading Style Sheets (CSS) in (X)HTML documents or standalone for conformance to W3C recommendations.
W3C markup Validation Service
A free service that checks documents like HTML and XHTML for conformance to W3C Recommendations and other standards.
Web Standards Project
The Web Standards Project is a grassroots coalition fighting for standards that ensure simple, affordable access to web technologies for all.
To have your link added here it should be informative and helpful to web designers, and strike me as more than just an advertisement for some specific web design tool.