The ID will still be around awhile- I guess sooner or later every forum 'purges' inactive members. I'd hope someone would notice a sticky would be leaving, but the links, assuming the websites that hold the data they refer to are still around, would remain in Cyberspace. It would just take someone else to collate whatever remained.
For instance- and not to self-promote but only because it's within my personal ken if you will- the arcane article 'Replacements & Reconstitution' written by my good self and posted only at TDG 'The Design Group' would have surely crept towards the doom it deserved only I noticed TDG had gone. I thus had the only remaining copy, and though there are many who would no doubt shoot me for doing so, brought it back from the brink.
There are far worthier articles, but the concept is the same. If the- sometimes- sole place it was hosted goes, only the author- and anyone who managed to copy it- has a remaining copy, though there are some internet archives where it is possible to recover material because they keep copies of old internet 'snapshots'. It's sort of internet archaeology.
Tactics are based on Weapons... Strategy on Movement... and Movement on Supply.
(J. F. C. Fuller 1878-1966)