Search engine marketing refers to the topic of encompassing many aspects of search engine optimization and e-marketing / e-commerce activites.

Some of these e-marketing techniques are:

Buying online media : Purchasing clicks or impressions or leads is a popular way to get traffic to your site. I will further break these categories down to explain how they work.

Pay per Click (PPC) : This means that you pay X amount of dollars per click. The big players in this area are google and yahoo. You can bid on keywords for a minimum amount (generally 5 to 10 cents a click) to get qualified traffic to your site. Of course there are some issues of click fraud, so factor that into the cost per click

Pay Per Immpression (PPI) Not to be confused with pay per inclusion. This is traditionally known as buying placement of an banner ad. For this you would buy X amount of impressions at a rate of 1000 impressions. Prices like this range from a few dollars per thousand impressions to hundreds of dollars. The more targeted your traffic is then the more the cost will be.

Pay per lead (PPL) This is the idea that you will pay someone X amount per transaction. Typically some company will want leads to follow up on and they will pay for each lead that is not bogus. Prices range from a few cents to hundreds of dollars depending on what the lead is for. It all depends on what the lead is being used to generate and how qualified the lead has to be.