In Keyword Planner, formerly known as the Keyword Tool, you can get search volume and traffic estimates for keywords you're considering. Unfortunately, when Google transitioned from Keyword Tool to Keyword Planner, they stripped out a lot of the more interesting functionality. But you can make up for it a bit if you take the information you learn from Keyword Planner and use Google Trends to fill in some blanks.
A very popular and highly competitive keyword on Google search engine is "making money." It has 85,300,000 search results, meaning that millions of websites are relevant or competing for that keyword. Keyword research starts with finding all possible word combinations that are relevant to the "making money" keyword. For example, a keyword "acquiring money" has significantly fewer search results, only 61 000 000, but it has the same meaning as "making money." Another way is to be more specific about a keyword by adding additional filters. Keyword "making money online from home in Canada" is less competitive on a global scale and therefore easier to rank for. Furthermore, keywords also have various intents which can affect whether the marketer would want to target that keyword. Multiple tools are available (both free and commercial) to find keywords and analyze them.
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The reason I sometimes use this facility with the GKP is to find volume amounts for the keywords I’ve chosen. But, these days, it’s not so important. As long as the Long Tail Keyword makes sense and is something I would put into a search engine, then it’s good enough. Sometimes the most blazingly obvious keywords are often over looked by eager, trying-to-be-clever marketers. Sometimes you need a tool to highlight them.
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).