Google Adsense

See one of my AdSense checks from April, 2006.
Note: Today, I earn much more than the amount on that check. The reason I do not have a more recent check to display is Google pays me by direct deposit now.
Here's a screenshot of my earnings taken during the middle of November, 2011.

What is Google AdSense?

AdSense is a nice way to monetize your traffic, and it's very easy to implement. It's one of my top earners and has been since 2003. Google.com earns most of its revenue by allowing other website owners to advertise on their search result pages. All this is managed through a program they call AdWords.
Now you can earn a share of the revenue that Google earns from AdWords by displaying these same text ads on your site.  In other words, you're helping Google advertise and they pay you a percentage (roughly 60%) of what they earn.
This program is called AdSense.
Every website owner should at least consider the program.  Even if your site is just for information purposes, you can still participate and make decent money with AdSense -- or at least enough to fund your website.
So if you are one of those people that doesn't like the idea of paying for a site, this is an excellent way to earn your money back and then some.

How AdSense Works

Don't like to read a lot of text? Watch my video on how AdSense works.

How Much Can You Earn With AdSense?

The commission you receive per click depends on how much advertisers are paying Google for the particular ad. You will earn a share of that amount.  I've heard of earnings anywhere from 2 cents to $15 per click.
So it is logical to believe that keyword phrases like debt free, employment, make money, mp3, sex, etc. may earn you more per click since these are highly competitive keywords that are searched for quite a bit on the web. 
Advertisers generally pay more for popular terms because they are searched for more.
Even though Google will not reveal how much you are earning for each ad that is clicked from your site, you can still login to your account at any time and see the total amount of revenue you've generated that day, week, month, year, etc.
For example, if you see that you've made $12.60 today from 9 clicks then you can calculate that your average click-thru commission was $1.40 per click.  That's as detailed as their stats will get.  Also remember, that's only an average.  You won't know how much each specific ad brought in.
The amount you'll earn also depends largely on the amount of targeted traffic you receive to your own site, how well the ads match your audience's interests, the placement of the ads on your pages, and of course the amount you receive per click.
Ideally, you should create a site on a topic you know a lot about.  That way you'll have a much easier time creating a generous amount of content on that subject.

My Google AdSense Earnings

I have been receiving monthly checks from Google since 2003, and I've read numerous success stories of websites earning 5 digit incomes per month with AdSense. 
Now, I will admit, a 5-digit commission in a single month is probably not the norm for most participants. 
I promote AdSense on 6 of my websites (2 blogs, a forum and 4 static sites) and my monthly checks are usually around the $7,000 mark.
My sites have been around for a long time and I have a great deal of traffic so that's a big reason why I earn so much. I promote my sites on social media, create YouTube videos etc. Making a lot of money with AdSense is all about numbers. The more traffic you have, the greater the earning potential.
My checks weren't always this large.  I think my first month's earnings in 2003 totaled less than $20. However, as my traffic increased, so did my checks.