Keyword Tools: More Options

Not long ago, a reader made a comment about good tools to research PPC terms.
To complement information provided by Adwords there are many tools available.
I came across two more websites that provide keyword tools that can be used as a complement in a research: KeywordSpy.com and KeywordDiscovery.com.
Both websites allow free users a limited access to some keyword information (for example, 10 top search terms) and, like Wordtrack, they have a free trial option.
To get access to all the features both websites offer you have to pay but the data they display for free can give you some tips and useful info. The type of information this tools provide can be valuable for Search Engine Marketing, Pay Per Click campaigns and Search Engine Optimization. I think that a good research tool is the one that uses a big amount of data from different search engines.
With this type of info you will know what people are searching on the Internet and which search terms generate the most traffic. With this type of tools you can research the best terms you should target to expand your online endeavors.
I tried both tools myself and was surprised to see the search results in some categories.
See you soon.