It's actually not so much about free consulting where I help them, it's more the other way round: they help me figure out how to improve the software by showing me what they've built or talking about what they want to achieve.

It's more of a market research exercise than freemium consulting.

That's not to say it couldn't also turn into a profitable exercise through up-selling consultancy, but that's not the primary goal.

Oh, I get the idea that the market research has a benefit as well. However, a major issue with Open Source development is funding it so that it becomes self-sustainable, especially for situations where the code requires significant work to keep it up to date.

I feel the gem in this article is the freemium idea for consulting on open source development.