Keywords Part 2:
 
There are three different keyword types: keywords for browsing, keywords for comparing and keywords for buying.
 
Keywords for comparing are usually the keywords that work best for search engine optimization. People who use that keyword type are looking for a solution to their problem and they are ready to buy. To get best results with your search engine optimization efforts, you should concentrate on that keyword type.
 
Most people use a two to four word phrase in a search, so phrases are very effective. Single words cannot be promoted effectively because they are not very targeted. Internet users who use four-word searches are more likely to purchase goods or services than those using fewer words (source: Oneupweb Research).