It should be noted that individuals searching long tail keywords are likely farther down an acquisition funnel and more apt to perform an action.
Example: "shoes" gets millions of searches a month, is very competitive, but broad/vague. "Women's red Nike running shoes size 6" is a specific, low competition, long tail search. This individual knows exactly what they are looking for and are more apt to purchase.
While this isn't always the case, many companies have become successful by leveraging long tail queries. Amazon being the biggest! Chris Anderson's The Long Tail better describes this phenomenon. There are more long tail searches than there are fat head (short tail) searches. So if you can invest some keyword research muscle into understanding where your long tail keyword opportunities are, and then provide the best resources/content to deliver that information to users, you'll site will be better set up for success.