It turns out someone (could be you?) wrote a Medium article about open-source software using the "free as in puppy" metaphor, although I don't think that they really used in the same way you are here with regards to a corporation using the open-source community to functionally receive free labor. I'm definitely going to add it to my mental list...

[1] https://medium.com/swlh/free-as-in-puppy-5b7eb1bf3908

Wasn’t me. Gifts bearing obligations come in a lot of shapes and sizes, I just always found the puppy metaphor very compelling and so I like to use it.

(As a mental exercise sometime, go to a pet store and figure out how much a “$12 hamster” costs once you get everything you need to set up and maintain a habitat.)

This is a wonderful description of "free" to go along with "free as in beer" and "free as in speech", thanks!

It's a beautiful metaphor.

Puppies can bring a lot of joy, but they certainly bring obligations.

Really spot on.

I've not heard this one before. Like a White Elephant but useful.

https://en.m.wikipedia.org/wiki/White_elephant

This is such a perfect addition to free as in beer/speech. Really quite surprised I haven't seen this more often, going to be using it haha