It doesn’t work. Craigslist knows how I feel:
It’s great that you have decided to start a blog, or a new webzine, or to publish your latest book, however it is damn nervy to ask writers to commit to writing articles (such as the gaming people who want FIVE articles per week) for free. A professional writer doesn’t need “exposure”, they need money. Professional writers don’t waste time working on spec for startups, they only work on spec for established publications. Would you ask a hairdresser to style your hair for free because you couldn’t pay them but offer them the “exposure” of telling everyone who did your hair?
If you want professional writers – PAY THEM.