My fuzzy impression is that vandalism tends, as is usual for such things, to be infrequent and unsystematic. So the larger and more persistent rest of the community can absorb the impact, and clean up after it.

Sounds a bit like Ted Nelson's notion of hypertext (pre web)!
Also like the original web. Tim B-L's original Next-based browser had editing (thus POST). Mosaic was great for web popularity, but one wishes there had been a nice Xlib "text field" widget lying around, which NCSA could have been encouraged to include. Things quickly became broadcast only, and had to wait for forms to recover even a little. :( Imagine an alternate timeline where...