1. Hustlers and schemers, who want to get rich quick (usually the folks that like spam, blackhat SEO and 'hustle culture').
2. Folks in 3rd world countries who see this as a ticket out of poverty.
The former are a disaster for any good community site or service, and the latter have the potential to become the former, since 'spam the crap out of a service for the chance to make more money' becomes an enticing proposition. A big digital marketing forum shut down its revenue sharing because these folks flooded it with low quality crap, the likes of Medium and Quora have become hellholes due to the same incentives, and crypto based 'pay to earn' games have literally led to people starting up sweatshops to make money in them.
Having it also cost money to use the site will help a bit, but it'll also filter out many good users due to not wanting to spend money on a subscription, and create a mental calculus of "can I make more from my content than it'll cost me to sign up", which isn't ideal in itself.
from my experience, there will be a LOT more ne'er do wells being filtered than good users. Not because there aren't a lot of good users, but simply because there are a lot more low effort ne'er do wells attracted to internet forums.
Other users can still browse at the very least. I think this will capture that nice medium of "good user who doesn't mind a little incentive". Because ofc the highest quality users aren't posting their ideas on public forums at all
I don't think that's true. I published some of my privat projects only on reddit because I want to put them out there, but do not expect people to interact too much.
Not saying your project isn't high quality, but generally the most consistent stream of high quality projects has someone paying for them.
No, for privat projects I am mostly reinventing wheels. But, in some sense, I actually pitched them collectively during my job hunt.
My interests are spread pretty far, so my hobby projects range from building ambisonic microphones over reimplementing interesting algorithms like WFC to implementing Navient Stokes equations in JAX to optimize airfoils in a differentiable CFD simulator.
My new job reflects that, I am pretty happy with that :-)