Thu Jan 10 07:02:51 PST 2019

terms actually make up less than 30% of the overall searches
millions of unique searches that might be conducted a few times in
any given day (or even only once, ever!), but, when taken together,
through search engines

Understanding the search demand curve is critical, because it
information not directed at any particular single, popular query, but
rather simply exposing the myriad of human thought, research, and
opinion to the spiders of the search engines
As an example, below
small number of queries sending larger amounts of traffic alongside
the plethora of rarely-searched terms and phrases that bring the bulk
of our search referrals:

Resources
Where do we get all of this knowledge about keyword demand and
keyword referrals? From research sources like these listed here:
Google Insights for Search
Google Trends Keyword Demand Prediction
Microsoft AdCenter Keyword Forecasting
We can see that Google is predicting both the cost of running
campaigns for these terms as well as estimates of the number of
clicks a campaign might receive
You can use these latter numbers
popular a particular keyword or phrase is in comparison to another