What are Long Tail Keywords in SEO?
Long tail keywords are often misunderstood by SEO practitioners. Many people incorrectly believe them to be longer keyphrases with more words them. (see this page as an example) This is wrong. A long tail keyword is a keyword (or more accurately keyphrase) which is rarely used in search engines and therefore has low traffic. Examples of which are 'cleethorpes web design', 'SEO Linconlshire', 'weight loss surgery in Manchester' or 'flame patterned contact lenses'. A related concept is 'niche marketing' which is not covered in this article.
The moniker 'long tail' comes from a statistical concept called the 'normal distribution'. A normal distribution is a recurring phenomenon that appears throughout nature. An prosaic example follows: imagine you question 100 women at random and ask them how many pairs of shoes they own. You will probably see a frequency graph something like this:
As you can see, most people are gathered around the center value (the mean) and fewer people appear at the extreme end of the graph.
The outlying values at the extreme end are called the 'tails', and in SEO the concept of long tail means the infrequently searched key phrases that, if plotted on a frequency graph, would appear towards the outlying ends of the frequency distribution.
Take the following example:
This graph shows the relation between the frequency (or salience) of a phrase and the number of searches done in a search engine, note that this is a one tailed normal distribution. This is a simplified explanation so the actual graph would be slightly different.
As you can see on the graph, the shaded area represents the search frequency for low volume searches. In this case, the low volume searches approximates to about half of the volume of the graph. Therefore, the number of long tail keyword searches for this result would be 50% of the overall search traffic.
For a more detailed treatment of the normal distribution see this page.
Why are long tail keywords important?
Some SEO experts claim that up to 80% of search traffic can come from long tail keywords. Personally I believe this to be a great over-exaggeration, and in some cases, can be used as an excuse to appease clients when their high frequency, targeted keywords do less well in the search engine rankings results. The actualy figure depends on where you draw the division between long tail keyword and high frequency keywords, and on what shape your traffic curve is. It also depends on how competative your targeted keyword is. If you target a page at the keyword 'software' you will find it very difficult to get to the first few pages of google, but if you target the keywords 'enquires management software' that would be much easier to get to the top. Therefore, focussing on long tail keywords, expecially at the start of a new SEO campaign is a good idea for drawing early traffic.
Another reason for looking at long tail keywords is the conversion rates. Specific keyword searches tend to have much higher conversion rates, for example, if you are a shop in cleethorpes selling mens clothing, then you will have a much higher conversion rate for 'cleethorpes menswear' than you would for 'mens clothing' - even if you were on the first page of google for both phrases.
Should you optimise for Long Tail Keywords in Search Engines?
This is a difficult question to answer, and depends greatly on the type of site you are promoting, and the budget. If your site is niche or your budget is small, then definately, your focus should be on the long tail keywords which are more relevent to your site, and will get you better quality traffic. If you are promoting a site in a competative market, and your SEO budget is good enough, then you are better off optimising for more competative keywords, and then using adwords for the long tail keywords, which will be relatively cheaper. You will find that when optimising for the competative keywords, a good proportion of search engine referrals will come from long tail keywords anyway, although if you are doing your job properly, your ratio of long tail keywords should not be anywhere near 80%.