"An open company differs from an open source project in that an open company is a formal legal entity, and needn’t be about software."
The set of employees of an open company is much, much smaller than the set of people working on whatever-it-is that the open company nominally "owns"--really it's a commons. The only reason to have employees at all is to formalize access to private data such as passwords and private user data.
Gittip, for example, has one employee, me. If you counted up everyone who has weighed in on GitHub we'd have maybe 20 or 30 community participants by now? Many more depending on how you draw the lines.
If I understand you right, the "requirements" would apply to the small set of people with access to private data, not to the majority participating in building whatever-it-is together.
It's fun, and adding/fixing a feature for everyone means they might add or fix a feature for me.
What I can't answer is: Why would someone agree to [do data entry/handle customer support/agree to be legally liable] without any compensation?
Those activities aren't fun, and if I handle customer support for you there's nothing in it for me.
Further, a lot of open-source programmers are getting paid. See [1] for Linux, the Mozilla Foundation for their applications, Joyent for Node.js, &c.
StackExchange is a huge network of volunteers helping to answer other people's questions, for no (real) compensation.
They might not be fun for you, but I think there are plenty of people that just like to help other people.
There's volunteering and charitable organizations that do mundane work, right? I guess this is just a different type of public service.
I'm actually not clear why this is a company instead of a non-profit foundation. It says:
"An open company differs from a non-profit organization in that an open company does not itself accept donations, and it does not compensate its employees. From the open company’s point of view, whether and how its employees receive money and for what, is undefined."
A non-profit can also not accept donations and not compensate employees, so the only thing that differs might be how employees receive money, which I don't really understand here.