I hear many writers refute idea of writing free content. While I agree, in simplest terms, it is "something for nothing", benefits of free content actually outweigh down-side of writing for free. Is it really for nothing?
--- The Battle for Content ---
The competition for content is fierce. Every Web site owner wants content and hundreds of writers want their content visible on Web. There are so many free Web sites that you can literally advertise your goods, services, and knowledge globally for years without spending a penny.
Of course, there is a cost involved in writing free content---time. However, cost in time units is only a fraction of money that would otherwise be spent in getting kind of coverage available by supporting content sites with free articles.
--- What about my income producing articles? ---
The idea is not to spend all day writing free content. Generally, once you've completed your articles for paying markets, take an idea and generate one free content article. I usually select a topic about which I can generate an article in a few hours. Don't spend more than two hours on article over an entire day---use it as a gap-filler.
The point is to be able to generate a short article that provides a general overview of your knowledge or work---don't dive too deep. If someone likes your work or idea, let them come to you and pay you for a more, in-depth version. Call it "testing waters."
--- Exercise Your Brain ---
One of benefits I've found to writing free content is in exercising my brain. I get a chance to generate a short article about something I know without added pressure of acceptance and deadlines. This is where you get to write for fun of it and be able to produce industry contacts and resume fodder.
--- Resume Fodder ---
Yes, resume fodder. If some popular site picks up your article, you can use it on your resume. Make sure that you write something that pertains to your areas of expertise. If you post something like "101 Fun Things You Can Do With Toilet Paper" and it's picked up by an unknown MLM site, I'd think twice about adding it to your resume.