Long Tail Keyword Demand

It is tremendous to be optimized for keywords that have a few thousands of searches a day. In fact, those kinds of keywords we just mentioned are only responsible for about 30% of the searches users executed in the Search Engines. “Long tail” search keywords are those that are accounted for the other 70%. Long tail keywords make up hundreds of millions searches that might be performed on the web a few times in any given day. However, putting together, they build up a huge demand for information via Search Engines. 
SEO experts point out that long tail keywords usually lead to better customer conversion rate as when people use long tail keywords to enter a site, they are more likely to purchase the products. A person searching for “SEO Experts” is probably just curious about that specific kind of expert, not that they need one. On the other hand, when someone searches for “SEO experts services in Singapore”, they may actually in need of one SEO experts on their hand.
 SEO experts in Singapore, Search demand curve
The meaning of Search Demand Curve is a fundamental concept you need to grasp when you first started SEO. Above is the Keyword demand curve. This curve indicates that the small number of queries sending larger amounts of traffic alongside the volume of less-searched phrases that bring the huge amount of our search referrals.
Keyword Resources:
You can see these below reference sources and tools for more information on keyword demand and referrals:
  • Google Adwords’ Keyword Tool
  • Google Insights for Search
  • Google Trends Keyword Demand Prediction
  • Microsoft Advertising Intelligence
  • Wordtracker’s Free Basic Keyword Demand
The most popular resource - Google's AdWords’ Keyword tool is a first reference to look into when you started your SEO keyword research. It not only recommends keywords and the accordingly anticipated search volume, but also foresees the expense that may incur when you run paid campaigns (PPC) for these terms. To determine volume for a specific keyword, be sure to set the Match Type to [Exact] and look under Local Monthly Searches. These indicate aggregate searches. The actual number of visitors you can obtain with these keywords will normally be much lower, depending on your ranking and click-through rate. Depending on your needs, you can search for other available sources or tools for keyword research that can work with more advanced data.
Sources: References from several reliable SEO forums and websites.