Marketleap Search Engine Marketing Tools (below)
Marketleap's "Link popularity check" is one of the best ways to quantifiably and independently
measure your website's online awareness and overall visibility.
Wordtracker - Search term suggestion tool.
Wordtracker suggests keyword phrases calculated by analyzing search frequency against the number of competitors for the phrase.
Google Rankings
Check your position in the Google search engine. Up to 1000 links deep.
Search Engine Optimisation & Marketing Info
Search engine optimisation services & search engine marketing services and free search engine optimisation tools by GlobalPromoter.com.
Yahoo Site Explorer
Site Explorer allows you to explore all the web pages indexed by Yahoo! Search. View the most popular pages from any site, dive into a comprehensive site map, and find pages that link to that site or any page.
Overture - Search Phrase Suggestion Tool
This tool reports the number of times users have searched for a particular phrase, and suggests alternate phrases to help your Pay-per-click campaign.
Google Adwords
More than 200 million times a day, people use Google and its partner sites to find what they're looking for.
So it's not a bad place to advertise!
Google Zeitgeist
The Google Zeitgeist page is regularly updated to reflect lists, graphs, and other tidbits of information related to Google user search behavior. Also see the Lycos Top 50 for reports on the weeks most popular search queries.