This is all making me really think!
Last year I was chatting to a very lovely professional writer, with whom I was sharing some hobby-research results, who described me as "generous" with my research and suggested I think in terms of monetising my output – blog or own website with advertising where I get a share, trad book, whatever. She was also scrupulous about offering to pay for whatever research she commissioned from me.
This was quite a shock(!) I'm not used to thinking in these terms for my hobby material. It's usually more the other way round – I would expect either to have to pay directly for my own publishing/hosting, or uneasily accept the trade-off of the social media model.
In that model, the hoster (be it MN or Facebook or Ancestry) just takes my content and/or my personal data as payment and monetises it for themselves by selling advertising space or the data itself, and their income can be any level from just keeping the servers on, to vast fortunes (data is the new oil, doncha know).
Then there's the academic model of funding by grants and institutions. That pays for the content. Who pays for publishing/hosting? Well an institution could pay the costs of hosting online, but when it comes to putting ink on paper that's a cost that has to be recouped by charging the reader (or the institution again via the library budget).
There's also the model of commercial publishing: the publisher pays for the content, may add value in the form of editing/illustrations, then pays for the cost of printing/hosting/distribution. They recoup these costs by charging readers.
Wikipedia: doesn't pay for content. Does pay for hosting. Doesn't charge the reader but asks for charitable contributions. AFAIK doesn't host ads or sell personal data.
Hmm, 'scuse me pondering out loud here. This is helping me think more about this landscape, and where I want to sit within it.
Also as you so rightly say, it's pretty easy to nick work wherever it's published.
I have a feeling that publishing through a formal hoster/publisher (even if it adds nothing in the way of editing or graphic design) may benefit me more than entirely self-publishing. It provides a well-evidenced publication date so I can demonstrate precedence. I should also be looking for somewhere that offers click-of-a-button citation formats, to incline users of my work towards acknowledging me rather than omitting it as a chore through sheer laziness.
Need to contemplate further whether Academia.edu fits the bill...