Sometimes a problem is already solved elsewhere on the internet in an impressive fashion. Quite often people post these answers as well (with attribution to the original author). Of course, there is no effort on the side of the author, other than finding (or knowing) that external source.
What is our policies on such answers? Are they valid? They do answer the question after all. Should they be community wiki? Should they be comments? If they should be answers, are they eligible for being accepting or receiving bounties?