SEO Paid Service
Remember that there are billions of sites online, and all commercial sites vie for ranking whether they intend to or not-strictly based on the textual content that the search engine spiders find within their code.
There are some funny things that happen with optimization. Your site may be for a car sales company. You might sell leather "bras" to protect the front ends of those cars. When a woman searches for braziers, your site comes up 5th on her list of lingerie shops. Why? Well, once again, remember that search engines are text based and look for words within your site to compare to a person's search terms. The fact that you rank so highly for the term bra "brazier" means nothing to you...but it is a real problem for the small lingerie shop around the corner who never ranks on any of their terms. Why does this happen? There are too many variables to understand completely, but there are some premium services that Google and Yahoo offer that help to guarantee very high placement.
One of these services is called "pay-per-click." What this means is that a company like yours will enter into an agreement with Google or Yahoo. You select a word or words that you think are dead ringers for your business and that you have worked into your coding in order to rank highly. Google or Yahoo will give you a premium placement link on the left hand side of their search engine window (you can look now to see others there) where you will be positioned on many occasions when someone searches for the words you chose. The catch is this: whenever someone clicks on that link, they go to your site, you rank more highly again, but you also pay for each of those clicks...sometimes in cents, and sometimes in dollars, depending on the popularity of the word (basically, how competitive is your industry and how many companies would like to rank highly using the same term?). Both Google and Yahoo have rates sheets that show you the popularity and costs of individual words...and that information is as interesting as it is occasionally shocking.
There are other pay per use services and expensive software packages available to help with SEO, but really, the bottom line is this:
Do you need it?
That's really up to you to decide...and, of course, how much you would like to spend!