Michael Jurewitz, a.k.a. Jury:
There is no doubt that free can lead to huge user bases and massive adoption. In the face of venture capital or existing cash stores, the siren call of free often sounds like a low-risk bet on future profits. In practice, free is a costly mistake that businesses and small developers should avoid, and users should run away from like the plague.
I'm going to assume for a moment that if you are reading this blog you care about making great product. Selling to lots of users is at least as important to you as being proud of what you build. Most folks in this camp aren't looking for a quick sale or to flip their business to a big buyer. If you care about the long term success of your business, you want users handing you money for what you build. You want the acquisition of money closely aligned with what makes your users happy.
This is a big part of why I've never made my iOS apps free, even when sales have been relatively slow.