It's already the case with some stuff from the '90s: there was important stuff announced and discussed on CompuServe and AOL forums that has not been publicly a

It's already the case with some stuff from the '90s: there was important stuff announced and discussed on CompuServe and AOL forums that has not been publicly archived. There are some personal archives out there, but they are pretty spotty. Often the only surviving (or at least accessible) record comes in the form of occasional quotes in other venues, like an academic paper from the 1990s that included a blockquote and a citation to a now-unreachable network address.