The phrase ‘long tail’ has become common terminology among the search marketing community ever since it was coined in 1994. Many a search marketer now abides by the long tail’s convincing theory in an effort to appear higher in natural search results or achieve a better return on investment from PPC marketing.

But while the long tail has boasted widespread adoption throughout the search marketing community, there does not appear to be a universal agreement among PPC specialists about exactly how many words constitute a long tail keyword. Nor does there appear to be agreement about which other metrics – price, search volume, competitiveness or purchase intention – should be used in defining a long-tail keyword.

Definitions of long tail keyword length vary greatly, from the vague mention of several words and nothing more than a series of words strung together, to the less vague description of 2 or more words, 3 or more words, and usually more than 2 words in length, to the very specific combination of 3-6 words and at least three, and some times as many as five words.

One definition rejects the long tail’s use in describing keywords of 3-4 words, instead referring to them as keyword gems, while others define long tail keywords not by definition but by using examples such as ‘myspace’ vs. ‘is myspace free to use in china’.

I’m hardly any better at providing a clear definition. In a previous post I wrote on the benefits of long tail keywords, my confusion over what exactly constitutes a long tail keyword made me shirk away from providing a clear definition, and I opting for a cop-out by providing an example of a long-tail keyword (e.g. ‘cheap remortgage for bad credit history’) along with a more generic keyword (e.g. ‘remortgages’).

So in search for a more definitive definition of long tail keywords, let’s break the long tail keyword down into its alleged factors to uncover its fundamental, defining properties and determine a clear definition of the long tail. Based on the above definitions of the long-tail, the following 5 characteristics all seem to play an important role:

  • Number of words in keyword
  • Search volume of keyword
  • Competitiveness of keyword
  • Price of keyword
  • Purchase intention of keyword

Let’s look at each of these 5 areas to see how useful they are in describing long tail keywords:

1. Number of words in keyword

It makes sense that a long-tail keyword contains a greater number of words than a short-tail or head keywords. But exactly how many words should a long tail keyword contain?

Although some definitions of long tail keywords specify a lower and upper limit for the number of words it must contain (e.g. 3-6 words), it makes little sense placing an upper limit on the maximum number of words a long-tail keyword can contain.

The more important question here is exactly how many words should a keyword contain until it is classed as long tail? In the definitions we looked at earlier, we’ve had mentions of anything over 2 words, anything over 3 words, and anything over 5 words.

Then there is the question of whether the number of words in a keyword really matters at all. For example, a short keyword such as ‘antique bingo clothing’ (3 words and very niche) might be considered long-tail, whereas a longer keyword such as ‘car insurance for women’ (4 words and very popular) might be seen as highly competitive and therefore not a long tail keyword.

So perhaps the number of words isn’t useful in defining long tail keywords. Perhaps search volume or competitiveness might be better.

2. Search volume of keyword

Again, it makes sense that keywords with low search volume should be classified as long tail keywords.

But exactly how low a search volume must a keyword have before it is labelled as a long tail keyword? 10 searches a day, 10 searches a month, or 10 searches a lifetime?

While long-tail keywords surely must have less search volume than highly generic keywords, clearly the definition of a long tail keyword should again not depend on a finite number. In searching for a definition, all we can say is that long tail keywords are generally searched for in less volume than more generic keywords.

3. Competitiveness of keyword

What about the competitiveness of a keyword? Are keywords with little competition long-tails?

If so, exactly how much advertiser competition is needed before a long-tail keyword becomes long tail no more? While Google’s keyword tool provides a scale of advertiser competition ranging from 0 to 1 to represent the competitiveness of a keyword, it does not have much practical use in reliably distinguishing between generic keywords and long tail keywords.

So once again, while competitiveness is definitely a defining factor in long-tail keywords, we can only say that long tail keywords tend to have less competition than those which are not long tail. We can’t say specify the exact amount of competition needed to distinguish between generic keywords and long tail keywords.

4. Price of keyword

What about the price of a keyword? Surely long tail keywords are those super cheap phrases you can bid on for $0.10?

Well, since the price of a keyword is linked to its competitiveness, it makes sense that long tail keywords would be cheaper than shorter keywords. And it also makes sense that the cost per click prices should be included in a definition of long tail keywords. But once again, it’s impossible to define exactly where the long tail cost per click cut-off lies. And since keyword prices are also closely linked to the purchase intention and the amount of potential profit which might arise from a sale, keyword prices naturally vary between industries and markets. Again, all that we that long tail keywords are generally cheaper than shorter keywords.

5. Purchase intention of keyword

Purchase intention is interesting. The theory behind purchase intention is that people who make longer, more specific search queries (e.g. ‘casio exilim ex-fh100 digital camera’) are more likely to have already carried out the majority of their pre-purchase research compared to people making shorter, generic searches (e.g. ‘digital cameras’). They are likely to be more informed about their buying needs, and therefore more likely to convert.

Longer keywords have long been known for their higher conversion rates, and many a PPC advertiser’s campaigns are built around a huge number of long tail keywords due to their strong conversion rates.

But does buying intention really form part of the definition of a long tail keyword? While it is true that some longer keywords (e.g. ‘casio exilim ex-fh100 digital camera’) exhibit high buying intention, other longer keywords (e.g. ‘how do clouds form in rainforests’) display little or no buying intention. Similarly, some shorter phrases (e.g. ‘buy apple ipad’) show significant purchase intent, while other shorter variations (e.g. ‘capital of peru’) display little or no intention to buy.

Purchase intention is therefore rather tenuous in its use in describing a long tail keyword.


While it seems that word count, search volume, competitiveness, and price all play some kind of role in defining a long tail keyword, there are too many exceptions for word count, search volume, competitiveness, and price to becoming defining features of the long-tail:

A keyword which receives 10 clicks a day might be labelled as long-tail to a large advertiser, and labelled as generic to a small, niche advertiser. The keyword hasn’t changed, but the description of it has depending on the circumstance.

Similarly, the keyword ‘casio exilim digital cameras’ might be seen as an uncompetitive long tail keyword to an advertiser spending $500,000/month on clicks, while instead being seen as a highly-competitive generic keyword to a smaller advertiser spending only $50/month on clicks.

Perhaps long tail keywords should not be defined in terms of absolute measures, such as number of words or number of clicks, but instead only used as a relative measure when comparing keywords? Rather than saying:

“This keyword here, ladies and gentlemen, is a long-tail keyword”

Perhaps it is better to say:

“This keyword here, ladies and gentlemen, is more long-tail than this other one”

How would you describe a ‘long tail keyword’? In terms of searches, clicks, CPCs, and competition? Or more in terms of a relative measure to compare one keyword (or set of keywords) to another? Your comments welcome below.

Alan Mitchell

Alan Mitchell is a Google AdWords PPC specialist, based in Melbourne, Australia, with a proven track record at improving return on investment (ROI) from Google AdWords. Find out how Alan can help your business.