Nice they're there. At the same time, it's amazingly easy for content to be removed from there - if someone objects or even if things are murky.
For example, all content from the old ezboard site was been removed based on the configuration of the current URL owners' robots.txt, and current URL owner is just a domain parker. Ezboard hosted a lot of content back in the day.
Hopefully it is just hidden and not deleted. But this is the main reason why alternative archive sites exists which ignore the original posters requests. Frequently used to archive posts from public figures which are suspected to be attempted to be scrubbed later.
Got any examples of these alternative archives?
A couple of pointers to the wider world of web archiving:
https://github.com/ArchiveBox/ArchiveBox/wiki/Web-Archiving-...