If you really don't want to spend any money, Pixelfed [2] is a good option.
Personally, I publish my photos on my own photography website and then syndicate them to Glass, Pixelfed and Instagram.
I don't agree, but i can't really formulate why. For example is 4chan social media, or Something Awful? I'd say no, they're forums. How is that distinct from Twitter or facebook? Fundamentally the model feels completely different to me. The idea of user centric feeds/content doesn't really fit. Maybe it's that the content is not the OP but the latest days worth of posts?
I see how on that metric HN is not forum-y but social media-y. But there it's the user vs content centric aspect?
Where does Pinterest sit?
Hummm, not at all sure.
Technically, Social Media is a super set of all of those things. They're all media platforms that primarily operate around user socialization (aka engagement). They are, by definition, social media, and in turn social media has been around long before Facebook (eg, slashdot, BBS, Usenet, etc).
I do agree there's a difference/nuance to be recognized here though (eg, old web vs new web social interactions). I think user vs content focus kinda misses the mark, as the truly key differentiator for me is what influences the activity, both in terms of driving people to post in the first place, but also in curating what they can('t) or should(n't) post. In other words, is the platform a community trying to serve it's users, or a company trying to serve it's stake/shareholders?
We have the tools to compete with proprietary platforms, we just need to commit to them.
A social networking platform with over 1 billion users (though I wonder how many of those a real people organically using the site) has a lot of inertia built into it for apparent forward motion, but if the thing that made it work falls apart, it will rot.
Also, for all the newly polished PR talk you hear from Zuckerberg these days about helping users, shit like the above and many other similar things is worth remembering. As the controlling individual at his company he both absolutely knows about these slides into enshittification, and has the power to change them, but apparently doesn't..