You can always make a folder for great articles within your browser 'favorites', and bookmark them. That's what I do.
As far as articles going 'missing', I don't know what you can do about that, except to copy the whole thing into a new document and save it to your computer.
omg, that's the whole point! By having the article here at FR it is automatically archived. Even if its only an excerpt it gives enough info for people to inquire if someone did indeed save the whole thing.
At any rate I like it the way things are.