Re-reading this thread there are some interesting and fair points made. I think there is a distinction that can be drawn with on the one hand, informal, amateur music making that perhaps should not be shared with the world (if at all) except with the consent of the performers in question - who may not wish their efforts to be disseminated by the same means as more "professional" or polished works - and amateur recordings of professional acts which may be of some present or future cultural value to preserve. As punkfolkrocker says above:
"Unseen and heard archives of amateur recordings
are recognised by museums as invaluable assets
whose holders should be positively encouraged to share
what they have of our hidden national heritage..."
This is the category the majority of my holdings fall into, either as audience or soundboard recordings, unauthorised though they may be. So, I have dipped my toe in the water and let one out via Youtube here (quality is not fantastic but I at least enjoy listening to the performance again): https://www.youtube.com/watch?v=kW7tF_hvUz8 (my thanks to Colin Harper for doing the upload on my behalf). Maybe this is one solution (subject however to possible take-down notices for copyright infringement...). Dime (dimeadozen) is another route, though I am not really sure how that works and I have a feeling it is a lot more complicated for both uploaders and downloaders (having had no success to date on the latter front).
Regards - Tony