I recently went through a large portion of my old blog. It's astounding how many excellent resources from just a few years ago have completely vanished due to link rot; in a few cases I was unable to find archives even on archive.org.
It's really sad, and more than a little disheartening.
Hosting the content or having your own copy of something is the only real way to be certain. I had the same experience and I've started saving all my work. Thanks for the idea about the blog though, I need to go back through mine and export everything.
It's really sad, and more than a little disheartening.