Firsthand Experience as an Expert Witness
This is one of the most important things I can tell anyone dealing with internet defamation, based directly on what I've seen handling social media and internet defamation matters as an expert witness: in a large share of cases, by the time the matter is being seriously investigated, the original content — the post, the profile, the review — is already gone. And the common assumption that "it's probably on archive.org" turns out to be wrong far more often than people expect.
The Usual Reasons
Posters delete content once they realize it's created exposure for them. Platforms remove content after user reports, even when the target never filed one. Accounts get deactivated or banned entirely, taking every post down at once. Reviews get quietly edited or withdrawn. And in some cases, content is deliberately deleted specifically because someone became aware they were being investigated.
How the Wayback Machine Actually Works
The Wayback Machine only has a snapshot of a specific URL if that exact page happened to be crawled by archive.org's bots at some point — and its crawlers heavily favor major websites and popular pages, not individual social media posts, specific reviews, or personal profile pages. Most of that content is never crawled at all, particularly on platforms like Facebook and Instagram that restrict what outside crawlers can even access. Relying on archive.org as a backup plan, instead of capturing evidence while it's live, is one of the most common reasons I see evidence turn out to be unavailable later.
The Practical Takeaway
Treat every piece of defamatory content as something that could disappear at any moment, because it often does. Capture it now — screenshots, source pages, timestamps — rather than assuming you or an investigator can retrieve it later.