Measures the number of times a keyword or a keyword phrase appears within a web page against the total number of words on this page.It is considered that Keyword density should not be more than 5% of the total words on the page.
Keyword Frequency
Is the number of times a keyword or keyword phrase is included within a page.
The theory is that the number of times a keyword appears on a page the higher its relevant it is to the search engines when they match that word to their users request. Don' go overboard or you will create keyword stuffing.
Keyword Prominence
Indicates how many significant keywords a webpage contains.These would be meta and title tags and topic titles, "h1 tags", subtitles "h2" etc, lists, "strong" and "emphasis".
Keyword Proximity
Refers to the closeness between two or more keywords.
Keyword Stemming
Stemming is the generation of several new words from a single keyword.
Example: Farmer: farming, farms, farm
This helps the copywriter create content that is more interesting while being able to avoid repetitions and keyword stuffing.
Stemming can give you a higher page ranking
Also, stemming helps protect websites from being accidentally blacklisted because of “keyword stuffing”.
Keyword Stuffing
Is the misuse of keywords to the detriment of the copy. Keywords should not be more than 5% of copy.
Keywords: Long Tail / Short Tail
The term ‘long tail’ was coined by Chris Anderson "Wired" magazine and is used to describe the strategy of targeting less-competitive niche markets. A long tail keyword is something like "Ralph Lauren Sweaters" while a short tail keyword would be something like "Sweaters". Many more users would search for Sweaters and the long tail would get a much lower percentage of users but might generate higher sales because the product is much closer to what the buyer is looking for.