Types of Online Advertising

Online advertising and ways that Web sites can make money takes several different forms. Here are common ways that Web sites make money:

Displaying Banner, Tower (or Skyscraper)
Banner ads that appear online have been around a long time. They are the rectangle graphic that appears on the top of many Web sites. The tower ads are long rectangles that usually appear on the left or right side of the page.
Displaying Pop Up (or Pop Under) Online Advertising
Pop up ads open a small new browser window when you open a Web site. Often if you visit many different pages you can have many browser windows open at the same time that can slow down your computer.
Displaying Keyword Advertising
Keyword advertising is very common. When you search for something such as "party supplies" at a search engine (Google, Yahoo!, etc.), the search engine often shows advertising based on the keywords that you searched for, in the search results on the page.
Displaying Rich Media Ads
These types of ads are being more prevalent. These are ads that will expand when someone puts their mouse over them or just automatically open and cover a large section of the page until a set time expires or they are closed.
Displaying Jump Pages
These types of ads are their own page that you have to click through to see the actual page you wanted to see. I often think of these types of ads as television commercials.
Commission Type Sales
Some Web sites have links to shopping and services on their sites and they get paid a commission for any actual sales or clicks from their site.
Surveys and Offers
Some Web sites will make you do a survey before you can get something for free. The Web sites are paid for each completed survey. Another way that Web sites get paid is to make you accept an advertising offer before they will produce the free item.

Full article about Online Advertising can be found on: http://familyinternet.about.com/od/internetsafety/a/internetads.htm