What is PPC and why Make Money through PPC?

For those who are unfamiliar with Pay Per Click or PPC. Here is an excerpt from Wikipedia that explains it well:

"Pay per click (PPC) is an Internet advertising model used on search engines, advertising networks, and content sites, such as blogs, in which advertisers pay their host only when their ad is clicked. (...)
Websites that utilize PPC ads will display an advertisement when a keyword query matches an advertiser's keyword list, or when a content site displays relevant content. Such advertisements are called sponsored links or sponsored ads, and appear anywhere a web developer chooses on a content site."

Most of the ads from AdSense Alternatives listed in this PPC list are contextual. Which means that as AdSense, you will not have to configure which ads your page must display - it will be done automatically and save you time.  In addition, if you were not accepted by AdSense, you might have even lower chances with CPM ad networks which usually receives ads from premium brands seeking very large websites (when you get to that size, you have someone in charge of advertising on your site...).