The keyword suggestion tool on SEO Book is one of the most advanced keyword research tools available. This tool offers information on various aspects such as:
This tool is pretty nice for keywords. It pulls the data straight from Overture which makes it a bit more accurate than most other keyword suggestion tools.
This is a pretty handy tool where you enter a search phrase and it will go through and find all the sites that come up for this search phrase with the word "Add link", "Add site", "Add URL", "Add Webs
I use this tool all the time when doing keyword research. It offers a fairly long list of keywords and unlike Overture, it offers both singular and plural data.
Wordtracker offers pretty reliable keyword data. Every once in a while you may find something that is out of place, but it's pretty easy to just ignore this and use the rest of the data.
This tool opens up a number of useful domain and host related information such as age of domain, registrar, owner, similar sites on the same IP and some other things as well.
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