I was searching Digital Point's Keyword Suggestion Tool http://www.digitalpoint.com/tools/suggestion/?keywords=sex&country=us & was wondering how accurate are the results given by WordTraker & Overture. I heard somewhere that never rely on results by overture because this is inflated. What's your opinion on WordTracker & Overture for keyword research as how many times those keywords were searched in search engines?
Both tools are hardly accurate. They are good for archival analysis as search trends change daily. Again, both use different algo to reach their figures. If you want to assess accuracy, simply use a third party tool to cross validate their results.
Just use them as a reference, but not a factor in decision. Just as any other SEO tools, it's not 100% accurate.