Free Software Business Model

Just read Jonathan Schwartz's post on software pricing. One thing that dawned on me is this quote:

It's far easier to convince a customer to pay for a product they're already using, than one they haven't even tried.

To me this is a new angle to the free software business model. One can offer their software as unlimited trial (free). When customers are ready to pay (most likely large enterprise customers), they can charge. Yes, it's far easier to convince a customer to pay for a product they're already using, than one they haven't even tried. This is happening now at Cisco for Confluence and JIRA. This is far better than just doing support and service. Limited trials don't work well.