Planet Ocean - The Search Engine Bible This is the bible the search engine professionals depend on. The be all and end all of how to get listed on the top of the search engines.  Get it and get ranked! Bruce Clay - Search Engine Relationship Chart The best visual explianation of which search engines work togeather and feed each other's results. Bruce Clay is also a respected and reputable search engine marketing professional. WordTracker - Keyword Search Popularity A database of terms that people search for. You enter some keywords, and we tell you how often people search for them, and also tell you how many competing sites use those keywords. Key Word Density Tool Keyword density calculator.  Counts the keywords on your page and in your HTML web tags. Ranking still has a lot to do with keyword density. You can't afford NOT to check your pages. Dead Link Checker Nothing may kill your ranking more and annoys your visitors than a site with a number of dead links on it. Inbound Link Checker Find out who is linking to you.  Great to ensure any purchased links are still active as well making sure any link exchanges you have are still up. Keyword Verification Tool Our verification tool checks to see if your site is in the top three pages of a search engine result for a specific keyword. It's important to be in the top 3 pages of a search result because most people using search engines don't go past the 3rd page. Trellian Keyword Research Tool