If you want to know who’s a newbie on a film set, just watch what happens at lunch. Major films have huge buffets laid out for cast and crew, and the newcomers can’t resist. It’s FREE! Over time, of course, the old-timers come to the conclusion that it's just lunch, and the crew gets a bit more jaded and learns some self-restraint as well.
The first time a previously expensive good or service is made free, we’re drawn to it precisely because of the freeness. The fifth time or tenth time, not so much.
Free online has two distinct elements, then. Breakthrough free, like the first free ebook or the first free email service, and sample-this free, which decreases the cost of trial and lowers boundaries of the spread of an idea.
But they shouldn’t be confused. As the market for free gets more crowded, we’ll see more and more people promoting their free products, stuff that people used to have pay for. A complete shift from ‘you will pay’ to 'it is free' to ‘I will pay for ads to alert you it’s free' to ultimately, 'I will pay you to try it'.
Free by itself is no longer enough to guarantee much of anything.