I recently needed to use the documentation for HTMLHint, only to find it had been deleted. So I went on Waybackmachine, and there it was.

I ended up going on the repo and asking them to undelete it, which they did, but in that moment I was lucky waybackmachine had it. This is one of hundreds of times I've used it.

The Internet Archive?! A lot of old (and not-so-old) websites are only available on Wayback Machine links. I've gotten a lot of old books from the Internet Archive (as in published in the 1700s, 1800, 1900s), they have almost everything pre-early-20thC that I search for. When I was getting into Forth and learning about Snobol, for example, they have a crapload of books and documents about both. And for lot of classic stuff from the 1970s and since unavailable anywhere else online[0] you can borrow an ebook free. Also I've got some great films and documentaries from there. Etc. I'm on there nearly every day, it's one of the very best sites online to search for stuff.

[0] i.e. instantly and free.

A terms of service disappeared. Gonna find back that Old EULA on archive.org

My non-profit org -- densho.org -- documents and preserves the history of the WWII incarceration of Japanese Americans. IA has partnered with us to provide the backend storage and delivery of the 1000+ hours of video oral history interviews in our online digital repository (ddr.densho.org). Their support has been invaluable to our mission to make our materials freely available.

The wayback machine is fantastic and powers content like this:

https://www.versionmuseum.com/history-of/apple-website

Recently I needed to run an old 16 bit windows program. I found a windows XP iso complete with a valid serial key on internet archive old software library.

Finding copies of long out of print books.