• Threadwatch - A popular community blog on all things search
• SearchEngineWatch Blog - SEW, operated by Danny Sullivan, is one of the most respected sources for SEO and search news inside and outside the webdev community
• SEO-Scoop - Donna Fontenot's personal and often introspective take on SEO
• StuntDubl - Todd Malicoat's SEO tips and tricks journal
• Cre8pc Blog - Kim Krause Berg presents on usability, marketing, webdev, and the search markets
• Jim Boykin's SEO Thoughts - The owner of WeBuildPages, a reknowned development and SEO shop, Jim's blog is geared to industry insiders and those who want an expert view
• Matt Cutts - One of Google's search engineers, Matt is Google's official representative to the SEO world
• SERoundtable - Barry Schwartz's roundup of all things search related
• SEOBook - Aaron Wall's accompaniment to his excellent book on SEO
• Link Building Blog - Patrick Gavin and Andy Hagans of Text Link Ads combine for great advice on the subject of where and how to get links to your site
• Search Engine Journal - Loren Baker's collection of posts and guest writers about events and phenomenon in SEO/M
• Marketing Pilgrim - Andy Beal's journal of the search engine space and SEO events
• Google Blogoscoped - Philipp Lenssen's journal of Google events, with an SEO bend

SEO/M & Webdev Forums

• Cre8asite Forums - Cre8asite is an open community of dedicated SEOs, usablity professionals, web developers, and others who come together to provide some of the best advice related to online marketing and development on the net. It's also where you'll find myself (randfish) moderating and posting on a daily basis
• SEW Forums - Danny Sullivan's Search Engine Watch website's online forums. A place where many high visibility folks in the SEO/M space come to post
• HighRankings Forums - Jill Whalen, a very well-known and respected SEO, runs HighRankings, a place where you'll also find experts like Scottie Claiborne, Dan Thies, and Alan Perkins
• DigitalPoint Forums - Shawn Hogan's incredibly popular (and somewhat noisy) forum on everything related to the web
• WebProWorld Forums - A large web development and SEO forum with a very diverse group of posters

Industry Conferences

• Search Engine Strategies (SES) Conferences - Each year, SES runs 6-10 conferences worldwide, including several shows in North America that I'll typically speak at
• WebMasterWorld (WMW) Conferences - 2-3 Times each year, Brett Tabke, the owner of WMW, runs conferences that attract a large group of SEOs
• Ad:Tech - An interactive marketing conference that has begun to address many of the issues of SEO and search marketing as well
• SEO by the Sea - An industry insider event sponsored by Bill Slawski, as well as a blog on SEO events and subjects

How Search Engines Operate

• Modern Information Retrieval - The reference standard textbook on Information Retrieval Science by Ricardo Baeza-Yates
• How Search Engines Work - from Danny Sullivan in 2002
• Search Engine Reference Page - from Wikipedia
• The Anatomy of a Large-Scale Hypertextual Web Search Engine - by Larry Page & Sergey Brin, founders of Google
• A Comparison of Search Engines and a Guide to How they Operate - from Berkeley University's Internet Guide
• List of IR Resources Online and Books/Publications - from Avi Rappoport of SearchTools.com

Link Analysis

• Search Engine Ranking Factors - From SEOmoz; see section on "Factors Affecting the Value of a Link" for link analysis information
• Block Level Link Analysis - From Microsoft Research on how search engines can segment pages into pieces of content to help devalue links from non editorial content

Keyword Research

• Wordtracker - Keyword research software
• Overture Tools - Measuring keyword popularity
• Digitalpoint KW Tool - Free data from Overture & Wordtracker (though shortened in each)
• Keyword Research Services - From Dan Thies; $100 reports are worth thousands
• Dan Thies' Blog at Sitepoint - Coverage of a range of SEO issues with a focus on KW research
• Measuring Keyword Competition - HighRankings Thread (9 Pages)

Accessibility

• Dive into Accessibility - From Mark Pilgrim, a guide to making a site accessible in 30 days
• Making a Great Website for Everyone - From Carmen Mardiros of Mardiros Internet Marketing
• Mistakes to Avoid - From IBM's articles on WebDev

Information Architecture

• Louis Rosenfeld - Information Architecture expert and author of the O'Reilly Book on the subject
• Introduction to Information Architecture - from Subha Subramanian at Sitepoint

Duplicate Content Issues

• Copyscape - Tool to search for copies of your pages on the web
• Aaron Wall on Dup Content Penalties - Citing posts at WMW
• Review of Dr. Garcia's Speach at SES San Jose on Dup Content - From SERoundtable
• What is Duplicate Content - From Sitepoint Forums

Usability

• Steve Krug - Usability consultant and author of Don't Make Me Think, my favorite book on usability
• Kim Krause Berg's Usability Reports - A steal for a corporate review at $800
• Usability Guidelines - From the National Cancer Institute; a great list
• Website Usability Evaluation Form - From MIT

Web Design

• A List Apart - Blog and Resources for Web Designers
• Applying CSS to Web Design - from Intensivstation
• Using Pattern Design to Lay Out Web Pages - from 37 Signals
• Sample Web Color Schemes - from Return of Design
• Biggest Design Mistakes of 2004 - from Web Pages That Suck

Content Writing for the Web

• 50 Writing Tools - from Poynter Online
• Write Effectively for the Web - from the LifeHacker blog
• Resurrect Your Writing - from Digital Web Magazine
• Writing, Briefly - from Paul Graham
• The Nitty-Gritty of Writing for Search Engines - from Jill Whalen (of HighRankings); it's $50 but worth every penny
• Crappy Content - thread from HighRankings forum by Scottie Claiborne

Link Bait

• The Art of Linkbaiting - by Nick Wilson of Performancing
• Linkbaiting for Fun & Profit - by yours truly at Search Engine Journal
• Examples of Link Bait - from SEOBook

Community Building

• 20 Tips for Community Building - from Threadwatch
• Implementing a Forum - a HighRankings thread with lots of generalized tips on community, too
• Building an Online Community - from Digital Web Magazine

Press Releases

• Optimization of Press Releases - Paid services from SEO-PR
• Writing for the Press - From Michael Iwalaski in the HighRankings Newsletter
• Online PR and Press Release Optimization - by Lee Odden at ISEdb
• Press Release Service - From PRWeb (free and paid options)
• Press Release Service - From PRNewswire (also has free and paid options)

Public Relations

• Public Relations as a Submarine - from Paul Graham
• Trends to Watch in PR - by Erica Iacono at PR Week
• List of Popular PR Weblogs - from PubSub
• How to Get Blogged - from TechCrunch

Link Building

• Advanced Link Building Tactics - from SEOmoz
• 131 Link Building Strategies - from Chris Sherman at SEW
• Technique for Selecting Sites for a Link Request - by Eric Ward (see more articles from Eric, the godfather of linking, here)
• Jump Start Link Building (while dodging the Sandbox) - by Andy Hagans

Search Spam

• Google, Yahoo!,& MSN - Spam reporting links for each of the major search engines
• Debate on White Hat vs. Black Hat SEO Techniques - from SEOmoz, a discussion on the pros and cons of spamming the search engines
• Manipulating Search Rankings - An interview with Greg Boser of WebGuerilla in Wired News
• SpamDexing - Another name for search engine spamming; definition from Wikipedia

Website Analytics and Visitor Tracking

• Web Metrics - Book by Jim Sterne
• Key Performance Indicators to Track - from the Web Analytics Association
• Web Analytics for Retailers, Parts 1, 2, & 3 - by Brian Eisenberg at ClickZ
• Top 10 Ways to Use Analytics to Improve your Site - from Conversion Rater
• Web Analytics Blog - from Omniture

Selecting an SEO/M Firm

• SEOmoz's List of Trusted SEO/M Firms - I've personally met or worked with all of the folks on this list and can vouch for their ability and integrity
• Google's Recommendations for Choosing an SEO Firm - with advice on how to avoid companies that could hurt your site
• Resources to Help Select a Firm - from Lee Odden of TopRank Marketing
• Reputable SEO Companies - Thread from SEW Forums
• Checklist of What to Look for in an SEO Company - from Stuntdubl