I’m sure you have or very soon will have someone tell you that you should use their services because they are ranking #1 for a term that has millions of competing sites.  For example let’s say they rank #1 for personalized color:

WOW! They rank #1 for a keyword that has over 11 million competiting sites!  Not exactly.

1. The number 11,700,000 is an estimate of pages not sites.  I know of many sites that have over a million pages.  In other words 11 million people are not competing, the actuall number is quite lower (assuming anyone is competing at all).
2. These results are composed of pages that contain the words personalized and/or color.  Since these are common words it, it is a very large number.  Simply having a word on your page does not mean your are competing for it.
3. A good way of determining competition is to look at the quantity and quality of sites linking to the top results.  For the “personalized color” example the top sites average 5 backlinks each.  Five backlinks is not competitive.  If you got ten backlinks, you would crush the 11 million “competing” sites

If you have any SEO snake oil rants feel free to speak up