Adsense. Website owners who use Adsense get a percentage of the click charge from the Adwords ads on their sites.
Once you sign up and get approved for an Adsense account it's very easy to place their ads on your web site. Google will give you some HTML code to copy and paste anywhere on your sites web pages. Once you do this Google will crawl your site and show ads that are relevant to its content.
Their are a few different ways to promote Adsense on your web sites. You can use Adsense for content, Adsense for search, or referrals. You can use any combination of these as long as you stay within the limits that Adsense requires.
Adsense for content comes in either text or image form (you can choose 1 or both). The text ads come in blocks that look like Adwords ads and are for the most part more popular to use than image ads. If you try Adsense for content you can also select links units to put on your sites. Link units come in blocks of 4 or 5 phrases that will be relevant to the content of your site. When somebody clicks on them they'll be taken to a page of Adwords ads that reflect the phrase they clicked on. Using blocks of text ads is the most profitable way to use Adsense ads.
If you use Adsense for search you'll get a Google search box that you can put on your web pages. When one of you visitors searches for a keyword or phrase using this search box they'll be taken to the relevant Google search page, which will of course have Adwords ads on it. Once again, if someone clicks on one of those ads you'll get a percentage of the click charge.
The newest Adsense feature is it's referrals program. If you use referrals through Adsense you can choose from many different products and services to promote either with text or image ads. Adsense referrals are a lot like other affiliate programs - you need the visitor who clicked on the ad to buy the product or service that is being promoted to make a commission.
Adsense ad blocks come in many different sizes and formats. You can put skyscraper style ad blocks, link units, and referral ads on the outside portions of your web pages or horizontal, banner-style ads at the top, middle or bottom of your pages. Ad blocks, link units, and referrals also come in many smaller styles.
Adsense will give you many options on how ad blocks and link units will look on your sites. You can customize the colors and borders of them to look like a more natural part of your web sites.
There are some rules you must follow when using Adsense. You can't have more than 3 ad units, 2 link units, 2 search boxes, or 3 referral ads on any web page (and probably wouldn't want to anyway, as this would likely make your site look like it was obviousy built for the sole purpose of getting Adsense clicks). You also obviously can't click on your own ads or induce visitors to you site to click on them. This will get you permanently banned from Adsense.
Google sends out Adsense checks towards the end of the month for revenue earned from the previous month. You must have generated over $100 from Adsense clicks to get a check as well.
To make money from Adsense you'll need content-rich sites with a lot of traffic. It may take some time to create your sites and get the traffic, but if you keep working at it you'll eventually make a profit from Adsense.