Google prefers to not share long tail searches in this tool – because the tool is designed for Google Adwords advertisers. If advertisers bid on those long tails – they would have less competition and therefore pay less for the Adword, and therefore Google would make less money e.g. bidding on the term weight loss for girls under 18 is cheaper than weight loss.
To be able to rank in the search engines is an art that must be understood and finding the right Keyword tool that fits into your comfort zone is a must. What I mean by ‘comfort zone’ is having a keyword tool that doesn’t confuse you before you begin even searching. Some go into far too much detail than is necessary. All you need really are good long tail ‘common sense’ keywords that other marketers may have missed.
Keyword Discovery is a paid subscription service that offers marketers the ability to see keyword data across multiple search engines. They maintain one of the largest databases of searches, (nearly 38 billion) which are compiled from over 50 different search engines. The search data shown is a record of the number of times the exact keyword or phrase has been searched over the last 12 months across all 50+ search engines. You would assume that the search volumes would be much larger than any other tool because of Keyword Discovery’s access to data from over 50 search engines, but the fact that the keyword matching option is set to exact, greatly reduces the total volume. Unlike Google’s tools, Keyword Discovery does not collect or show data relating to paid search, such as Suggested Bid, Cost per Click, and Competition. Data is collected daily, but updated monthly. Although you must pay the subscription to have access to all the features, Keyword Discovery does provide a free alternative.
WordStream's Negative Keyword Tool reduces wasteful PPC spending and improves ROI by preventing your AdWords PPC ads from showing on irrelevant searches. Enter a keyword to get a list of negative keyword suggestions. Then select the ones that aren't relevant to your campaigns and export the results for use in your AdWords account. As a result, your ads will be more relevant to searchers, grab a much more targeted audience and reduce your overall ad spend.
In a nutshell, Long Tail Pro helps you quickly find keywords in bulk based on a seed keyword that you input. In addition to returning hundreds of related keywords, the tool also shows search volume (monthly search volume), advertiser bid, number of words, rank value, and my favorite Keyword Competitiveness (helps you judge the competition and keyword difficulty).