Another illicit practice is to place "doorway" pages loaded with keywords on the client's site somewhere. The SEO promises this will make the page more relevant for more queries. This is inherently false since individual pages are rarely relevant for a wide range of keywords. More insidious, however, is that these doorway pages often contain hidden links to the SEO's other clients as well. Such doorway pages drain away the link popularity of a site and route it to the SEO and its other clients, which may include sites with unsavory or illegal content.
In addition to measuring your website traffic, you need to track your conversion rates. For example, if, as a result of your search engine marketing efforts, your traffic doubles from 250 to 500 visitors per month, how many new customers did you acquire from the additional 250 visitors to your site? Do you now have twice as many customers as you did before? If you picked up 5 customers your conversion rate would be 2 percent of the new traffic (5 divided by 250) and 1 percent (5 of 500) overall.