AdWords Performance Grader is a free education for business owners who are feeling their way in PPC advertising.

FORBES: How to Improve Your Online Advertising Campaign

Small businesses have been among the most active users of a free tool that helps them manage their spending on Google PPC advertising, said Larry Kim, founder and VP of Marketing and Products for WordStream.

FORBES: How to Improve Your Online Advertising Campaign

You could specialize in pay-per-click (PPC) advertising, or make a killer social media manager.

FORBES: The Only Essential Skill You Need To Be Successful Online

Specifically, the company purchasing a PPC campaign pays the advertising publisher every time an advertisement, such as a text link or banner, receives a click.

FORBES: The Pay Per Click Model: Grey Line of Legality