Useful Tools

Keyword Tools:
Research: http://www.wordtracker.com/
Research: http://inventory.overture.com/d/searchinventory/suggestion
Research: https://adwords.google.com/select/KeywordToolExternal
Research: http://tools.seobook.com/general/keyword/
Trends: http://www.google.com/trends/

Domain/Server Tools:
Check Headers: http://web-sniffer.net/
Speed Test: http://www.websiteoptimization.com/services/analyze/
Webmaster Tools: https://www.google.com/webmasters/

Domain Tools:
Domain Tools: http://www.domaintools.com/
Popularity: http://www.alexa.com/
Popularity: http://www.quantcast.com/
Popularity/Trends: http://www.compete.com/
Popularity/Trends: http://www.urltrends.com/
Probe/Track: http://siteexplorer.search.yahoo.com/

Blog Tools:
RPC/RPC2 Ping List: http://elliottback.com/wp/archives/2004/11/21/a-list-of-rpc-and-rpc2-to-ping/
Ajax Polling: http://blog.jalenack.com/archives/democracy/
Social Tagging Widget: http://www.toprankblog.com/tools/social-bookmarks/
Social BookMark Widget: http://www.wolf-howl.com/tools/social-bookmark-script-widget/

Social Tools:
BlinkList: http://www.blinklist.com/index.php
Delicious: http://del.icio.us/
Reddit: http://reddit.com/
Spurl: http://www.spurl.net/
Squidoo: http://www.squidoo.com/
StumbleUpon: http://www.stumbleupon.com/
Magnolia: http://ma.gnolia.com/
Google BookMarks: http://www.google.com/bookmarks/
Furl: http://www.furl.net/