Check Google and Alexa Ranks - Use this tool to determine your Google PageRank, Alexa ranking, and the number of times you're listed on various search engines.
 

Predict Future PageRank - Use this tool to predict your future Google PageRank (PR).
 

Check PageRank on Multiple Servers -  PageRank sometimes varies from one Google server to another. Use this tool to check your website's PR on multiple servers. If you use this tool while Google is updating its PRs, you can get a glimpse of your future PR.
 

Check Keyword Density - Use this tool to find out which keywords are popular on your pages. The keywords will be graphically shown in a "cloud view".
 

Make Meta Tag - Meta tags allows for better indexing by robot-driven search engines and can boost your ranking in search results. Quickly generate meta tags for your web page.
 

"Bookmark Us" Script - If you don't remind people to bookmark your site, they may forget. This little script will help you retain some visitors.
 

Overture's Keyword Selector Tool - Not sure what search terms to bid on for your pay-per-click campaign? Enter a term related to your site and this tool will show you: (1) related searches that include your term and (2) how many times that term was searched on last month.
 

Overture's View Bids Tools - See how much people are willing to pay for a keyword in Overture's (Yahoo Search Marketing) pay-per-click program.