What is it? :: Promote other company’s products and services on your website. When a sale is made, you get a commission.
Most important skills needed :: PPC (Pay Per Click marketing), sales copywriting, web marketing
Best learning resources :: ReveNews, ABestWeb Forum, ShoeMoney, Rosalind Gardner, Affiliate Classroom
Recommended Book :: Make a Fortune Promoting Other People’s Stuff Online by Rosalind Gardner
What is it? :: A chronologically based website filled with articles, reviews, or journal-style writing. You can sell advertising or incorporate affiliate marketing on a blog to earn money.
Most important skills needed :: Copywriting, social networking, affiliate marketing, web marketing
Best learning resources :: ProBlogger, JohnChow, DoshDosh
Recommended Book :: ProBlogger, Secrets to Blogging Your Way to a Six Figure Income by Darren Rowse & Chris Garrett
What is it? :: Doing internet research for corporations, law firms and other small businesses.
Most important skills needed :: Librarian-style research skills, customer service
Best learning resources :: Entrepreneur.com’s Information Consultant Startup Guide
Recommended Book :: Building & Running a Successful Research Business: A Guide for the Independent Information Professional by Mary Ellen Bates
What is it? :: Providing professional services such as copywriting, design, photography, illustration, and programming usually billed on an hourly rate.
Most important skills needed :: Sales, customer service, trade-specific knowledge
Best learning resources :: Our Freelance Parent channel, FreelanceSwitch
Recommended Book :: The Business Side of Creativity: The Complete Guide to Running a Small Graphic Design or Communications Business by Cameron S. Foote