Any definition of internet marketing needs to come along with a definition of things associated with it such as affiliate marketing, network marketing, multi-level marketing and so on and so forth. Some of these are less legitimate than others. For example, affiliate marketing is a tough nut to crack unless you have a massive following or you understand how to build excellent squeeze pages and effective sales funnels.
Chris_D, great question. If you have a single product page that can have multiple urls with slightly different parameters, that’s a great time to use a rel=canonical meta tag. You can use rel=canonical for pages with session IDs in a similar fashion. What rel=canonical lets you do is say “this page X on my host is kinda of ugly or otherwise isn’t the best version of this page. Use url Y as the preferred version of my page instead.” You can read about rel=canonical at http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=139394. Bear in mind that if you can make your site work without session IDs or make it so that you don’t have multiple “aliases” for the same page, that’s even better because it solves the problem at the root.
A breadcrumb is a row of internal links at the top or bottom of the page that allows visitors to quickly navigate back to a previous section or the root page. Many breadcrumbs have the most general page (usually the root page) as the first, leftmost link and list the more specific sections out to the right. We recommend using breadcrumb structured data markup28 when showing breadcrumbs.