Dan (the original Jmol author) has an interesting blog series: How to make money from Open Source scientific software I, II and III. Three more blog items are in the planning. The deal with how to make money from open source scientific software. He wants to be able to skeptically review the software in his field, hence open source. But open source software development, at least in chemistry, needs funding, because there are too few people working on such software on a voluntary basis.
The articles discuss possible scenarios. Article I discusses 'Sell hardware' that comes with open source software, and article II discusses the 'Sell services' scenario, which still works in the GNU/Linux OS world. He argues that selling support does not fit the chem-bla-ics world: "First, scientific software targets a relatively small group of users, and at the same time, the development and support costs are often quite large." and "Why would a researcher spend $10000 on a support contract if the problem could be solved by throwing a graduate student at the open source version of the code for a few months?" Interesting arguments indeed.
Instead, he suggests, the service sold should be knowledge. The open source based company should sell knowledge, should solve customer problems using open source software. Each problem will come with specific needs, allowing indirect funding of open source development. And, yes, this is indeed how open source chemo-/bioinformatics software is currently development: as a mean to solve scientific challenging problems.
I'm looking forward to his next articles in this series.