Recently I was researching an issue and couldn't find the answer on stackoverflow, so I had to turn to Google. I kept finding links that seemed to be related to my my problem, but they referred to an older version of the technology and it was hard to tell what was still valid advice and what I should trust.
I was thinking about a feature of stackoverflow, where instead of asking a direct question, you could post a link to an external site (blog, article, discussion, etc), maybe with some comments. The voting of the question would reflect the value of the link (its currentness, value, etc), and the answers could give details about why the content was or was not still valid. It could work like community wiki, to keep the up/down votes of the link from affecting the person "asking" the question. Answers could still get reputation.
Also, anytime an answer to another question contains a link, it could be marked up to the "link question" if it exists.