I was the author of the answer with the archived link. In general I think that no, we should not provide archived links. I only used the archive for this specific link because, in my experience, The Daily Dot often deletes or modifies articles, making them invalid for future reference. Using an archive ensures that people are able to see what was present when the article was first linked, not anything else.
The problem with this approach is that when the original link stops working we can find an archive link using the original and replace it. But if the archive link stops working we will not be able to trace back the original link from it (https://archive.fo/QGtny) and the reference will be gone forever.
That is a good point. I had actually intended to create an HTML comment with the original URL just in case, but completely forgot about it when I got sucked into something completely unrelated.
Should we prefer original links to archives? (And create a snapshot in archive maybe).
Generally yes. As for creating a snapshot in the archive, I actually do that for almost all the links I post unless they are reproductions of redundant data like man pages, source code, or are on a site that is regularly archived already, like Wikipedia or Stack Exchange.
If the answer to the first question is Yes, then should we replace the archive links with original one when we come across it? (And point the author to this meta post maybe).
I don't think that's necessary, but I'm obviously biased.
Anyway, I've went ahead and found a more reliable source and linked to it instead.
Note: The reason I don't use the Internet Archive is because they retroactively exclude sites from the public if a robots.txt policy is in place, which is often the case when a website is turned into a landing page. Proof: https://web.archive.org/web/*/www.truecrypt.org and http://www.truecrypt.org/robots.txt