Wayback Machine (web.archive.org, 网站时光机)

Their Wayback Machine tool archive snapshots of webpages and allows youto browse the history of all archives:

By the Internet Archive organization:

But remember that if you archive too many in a very quick succession before the previous ones have been archived, even if manually through that plugin, your account/IP might get blocked, so just give a few seconds for the current archive to terminate before starting new ones.

This happened to Ciro in 2020-06-14, but then he emailed the admins as mentioned at: https://help.archive.org/hc/en-us/articles/360016379432-Accounts-Tips-Troubleshooting- and they re-enabled it.

As of 2021, it annoys Ciro very much that you have to wait for a few minutes for the archived page to become visible. That’s an eternity when you are writting a text and need to link to an archive.

It is also extremelly annoying that they sometimes change image URLs randomly after they’ve become visible. Why is that? E.g. Ciro saw breaks between different timestamps:

and aso betweeen im vs if as in:

so it is just not reliable enough to use generally.

It is possible to request social media pages you own to be removed from the archive in some circumstances: https://webapps.stackexchange.com/questions/143529/is-it-possible-to-request-to-remove-page-snapshots-from-a-personal-social-media

Some website specific techniques:

How to archive with an API:

One downside of Archive.org is that is is age restricted by some ISPs for containing adult containing, e.gn. notably mobile ISPs. Those idiots, sacrifice freedom of learning for a bit of innefective Pornography ban (色情禁令) protection.