SEO Basics: What makes a good Keyword List for SEM & SEO Copywriting?

Keywords (a.k.a. search terms) are the words and phrases that people use to proactively find what they are looking for in search engines such as Google, Yahoo or Bing. The choice of keywords that prospects use to find what they are seeking on the web is a critical factor in determining what sites are going to be served up in the Search Engine Results Pages (SERPs).

Definition of a Keyword:

A word that serves as a key to a code or cipher.
A significant or descriptive word.
A word used as a reference point for finding other words or information.
Any significant word or phrase, esp. a word used to describe the contents of a document.

Many of the top-ranking webpages, for any search query, rank […]