Clearly I'm a biased observer, but I really think people should take steps to archive stuff that is important to them. Of course it's terrible when large sites go offline and take vast swaths of the Internet with them, and we should continue to shame the ones that do it. At the same time, if something is really important to you, you shouldn't store it in the form of links to random third-party servers. One problem we…
I recently converted all my bookmarks to saved copies of the pages in Evernote. This means I have full text search over everything I "bookmark" -- still have the links -- and never lose it regardless of what happens.
In this process, I was shocked at the number of 404s I encountered from relatively recent (last 18 months) bookmarks.
Evernote is a bit of a wreck, but so far the combination of decent copy of page, browser plugins, tags, search, accessibility (phone clients, web client, some native clients) have made it my best option.