Online marketing is a broad, general term that implies making money through online promotion. Products can range from digital books, to brand new cars, to custom built homes, to health insurance and everything in between.

A person engaged in online marketing can make money whenever a transaction occurs. They can also make money when information is passed from one person to another. But exactly how does one make money from these goods and services?

There are four primary ways to make money online. I've listed them in order of least difficult to most difficult:

Method #1: Selling your own product or service. As long as you are willing to join an affiliate network, selling your own product or service is probably the easiest way to make money online. You don't have to understand marketing or website promotion. All you need to do is create a worthwhile product (or provide a service), create what is called a "pitch page", and then join an affiliate network.

When you join the affiliate network, your product becomes available to hundreds of thousands of online marketers. In exchange for a percentage of the sales price, these online marketers will then promote your product. Joining an affiliate network is similar to hiring potentially thousands of salesmen all at once. And the best part is you don't pay any fees until a transaction occurs!

Method #2: Generating legitimate, targeted leads for other companies. In order to survive, a company must have a continuous stream of potential customers or "leads". Without leads, there can be no sales, and any company without sales will inevitably close its doors. Because online marketing is so complex, it is easier for a company to focus on running its business while online marketers generate leads in exchange for a referral fee.

For a marketer wanting to generate online revenue, I believe this is an easy method because you are not asking for money from the customer; only their contact information. For my lead generation sites, I typically average a 30% conversion rate.

Method #3: Promoting (and selling) products and services owned by other people. If you would rather not create your own product or service, you can join any number of affiliate networks and then choose from hundreds of thousands of products to promote. When you engage in this type of online marketing, you become an Affiliate Marketer.

Personally, I think this a difficult way to earn money online because you need internet traffic in order to make sales. And unless you have a well designed website or marketing strategies, this path can be a very difficult for a new marketer to make money online.

Method #4: Advertising. This is pretty straight forward: develop a website and drive traffic to it and then sell advertising space on the website. You can charge per impression, which is called "CPM", or you can charge per click, which is called "CPC".

To get started in this type of marketing, you can sign up with either Google Adwords or a company called Adbrite. These two are by no means the only advertising networks you can join (there are hundreds of networks available). In my opinion, this is the toughest form of online marketing for a beginner because it requires highly targeted traffic (and lots of it!) to make this type of revenue method work.