Because someone who is looking for something that specific is probably a much more qualified searcher for your product or service (presuming you're in the blogging space) than someone looking for something really generic. And because long-tail keywords tend to be more specific, it's usually easier to tell what people who search for those keywords are really looking for. Someone searching for the head term "blogging," on the other hand, could be searching it for a whole host of reasons unrelated to your business.
When I finally made the decision the get Long Tail Pro way back in December of 2012 – I honestly had no idea how much this one piece of software would impact everything I do online. I knew that it would help me find more and better keywords right off the bat. But I didn’t know exactly how much it would positively affect my ability to actually make money online. I can say with confidence, that Long Tail Pro is the one tool that has made the biggest difference (by far), in my ability to get traffic to websites and actually earn money online.
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).