You should keep a copy of useful information on your own blog, and not just keep a link to the original. This advice may seem to violate netiquette or social norms, but there’s a good reason to do it. A blog or link to stackoverflow isn’t permanent, a personal blog or site can be taken down or moved and your information is lost. This goes double for rarely used or niche technical info and blogs.

I’ve had this happen to me at least twice in the last 2 years, bookmarked a useful blog with the intention to come back later and finish the project and … it’s gone. Google search for similar information comes up with nothing. The same goes for stackoverflow, the links are supposed to be unique to help people find information. However they do prune the data and links are not guaranteed to be always present, they can be deleted or removed. Blogs can be moved or the original author decides to stop paying for their website or whatever \_()_/

If you find something important, grab a copy of the original and store it somewhere. Do yourself and the world the favor, write your own version publish it online and reference the original author as it’s only the polite thing to do. At least then you’ll have a copy for as long as you need it.