Be your own librarian
One thing I learned when writing a book about the pipeline protest here is that what you find online is extremely fleeting.
Social Media overlords pull or block content that doesn't fit their "community standards" which, I learned, are more about ideology and less about sexual perversion or harassment. Or, a news website is short-lived; that happened a few times. Most commonly, people post things on social media that they later delete or make private.
Information moves, is hidden, or completely disappears. This is even more true now than it used to be because the places we are creating, storing, and sharing our information are owned by companies with ever-growing clearly illustrated agendas.
The nature of that protest was to say that every opposing idea was false and couldn't be proven. Or, people demanded the source. That wasn't such a bad thing, really, but I've always been one of those people who read a ton of stuff and can't always remember where I read it. "It was in a book with a blue cover," I might say, or vaguely recall reading it in a magazine in the archives at the local library.
With so much disinformation, spin, outright false reporting and its cousin, sloppy reporting, my old method of feeding curiousity with information and knowledge but not remembering where I got it from when pressed forced me to make some adjustments when I wrote that book.
I had to download and archive a copy of everything I would use later in reference. That meant Facebook videos, YouTube videos, and saving PDFs of web pages, as well as making screenshots of social media posts or comments.
During the protest, we figured out how to download a Facebook video on a computer by forcing Facebook into a mobile mode. However, they have since changed that. There are several websites that you can use to download videos from Facebook, YouTube, etc. Do a search for them. I am hesitant to link to them. YouTube, especially, is increasingly aggressive at pulling videos that go against their ideology, so if you see one there, you need to grabe a copy ASAP. Sharing it online is great, but when it's pulled, it's gone. Sometimes YouTube simply buries the video and makes it difficult to find in a search (e.g. "Out of the Shadows").
Websites can be saved as a PDF by going to the print feature in your browser, and choosing to download it as a PDF. Some websites, however, are so full of pop-ups and whatever else that they make a disasterous PDF. Because of that, I used a Chrome plugin (Print Friendly & PDF) that strips away all of the ads and nonsense and makes a clean PDF.
I save all of these on an external hard drive as well as in a cloud drive that has OCR capabilities so that I can search not only PDFs and files with text, but also images (i.e. screenshots from social media) that have text in the image. I also try to organize it all somewhat.
Right now, if you were to look up many of my sources for my protest book, you'd find that probably half are no longer online or at their noted location. But every single source and video referenced I can prove is legitimate because I saved a copy for my own research.
I'm noticing that people making videos that are likely to raise the ire of Das Social Media Jack Boots have also been offering MP4 downloads on their websites so people can download and watch and share without relying on the content controllers.
All of this to tell you that if you are passionate about a topic or are in any way working on a project or preparing to debate someone, or even if you just want to be able to look back and read what the news was saying from an earlier time, you should be doing this. It is not enough to bookmark a web page, or save a Facebook video to your saved list. Those things are mere links to a location, and do nothing for you when someone removes the content.
You must make your own copy that is not on the internet.
Even libraries regularly purge books to make room for new items. You have to think of the internet as a place not where things live forever, but where important or controversial ideas and content often have a very short lifespan.