SEO starts with choosing keywords. Most SEO people will run up front with their SEO verbiage such as "we will combine long tail keywords and short tail keywords"... What the heck does it mean?
If you ask the difference, they all will say something like this: "A keyword is by definition one word so it is short tail; when you associate keywords into keyphrases, then we talk about long tail"...
Mmmm, this is interesting but how to put this back into a understandable context?
Let's say you sell red snickers with blue laces.
A short tail keyword would be "shoes" - in the best situation ever, you are top 1, every one looking for shoes will land on your website - yoohoo, traffic jack-pot. Unfortunately, 70% did not snickers, 25% did not want red ones and 3% thought the blue laces suck... You are left with 2%, a bite from a giant market cake.
A long tell keyword would be "red snickers blue laces" - in the best situation ever, you are also top 1, every one looking for red snickers with blue laces will land on your website - not so yoohoo because the traffic sucks. No it is very good because the traffic will be very relevant and you will sell to 99% of them - yoohoo, optimal conversion rate. You may have a cookie but you share it with no one!
Now you really know what is the good, the bad and the evil with keywords!