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?

Some examples:

  • 4
    \$\begingroup\$ I would vote for community wiki + accept if shortest, however: does anybody (asker or answerer) get rep from accepting a CW answer, and if so, is it enough rep that coordinated abuse is worth worrying about? \$\endgroup\$ Sep 9, 2014 at 3:02
  • \$\begingroup\$ @algorithmshark I don't think you get any rep for a CW answer at all, but I'd guess the OP still gets 2 rep for accepting it. \$\endgroup\$ Sep 9, 2014 at 8:12
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    \$\begingroup\$ @algorithmshark I'm not sure if we want to accept community wiki answers. Here's an example: codegolf.stackexchange.com/questions/37357/… if we planned on accepting the best solution on the internet, it could discourage people from answering it. (The 50 language one is hard to beat, and could be accepted if posted as a community wiki). \$\endgroup\$
    – hmatt1
    Sep 9, 2014 at 17:20
  • \$\begingroup\$ The question we need to ask ourselves is: do we want to reward the best answerer or the best answer? On other SE sites there would be no question that an external source should be accepted if it does provide the best answer. So here, we should probably do the same if the linked answer does solve the challenge best. On the other hand, one could argue that we're about posting and solving challenges here, so only people who actually put any effort into the solving should be rewarded with the green checkmark. \$\endgroup\$ Sep 9, 2014 at 20:06
  • \$\begingroup\$ You should also consider the fact, that in many cases you may not have the legal foundation to post it as an answer. Attribution is one thing - licences is a different topic. \$\endgroup\$
    – Howard
    Sep 9, 2014 at 20:26
  • \$\begingroup\$ @Howard Of course, this is all under the assumptions that the licences are not a problem. Otherwise the answer needs to be deleted anyway. \$\endgroup\$ Sep 9, 2014 at 20:29
  • \$\begingroup\$ In the case of Polyquines I've accepted the CW now and can confirm that no one (not even the asker) gets rep for it. Still, it seems a bit disheartening to the people who actually put effort into their solutions. \$\endgroup\$ Sep 15, 2014 at 7:35

1 Answer 1


Outside answers are valid as Community Wiki

If a good answer to a challenge exists, it should be posted. This site is about finding the best answer, not just an internal competition. However, since the person posting the answer did not create, it wouldn't be fair for them to get the reputation for it, and so it should be communtiy wiki.

I believe this is the de facto method we have been using, and I'd like to make it official.

Of course, attribution is essential, and if someone doesn't want their work posted here, it should be taken down.

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    \$\begingroup\$ Another important nuance of this (which came up the other day) is how many changes to an external answer justify not making it CW. (Someone took an external solution and golfed it down by a couple of bytes.) \$\endgroup\$ May 25, 2015 at 22:45
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    \$\begingroup\$ One must be sure that the licensing for the external resource is compatible with the CC-by-SA that all content to Stack Exchange is licensed under. If it is not, then things can get messy. This would be the case especially when some other license that isn't compatible with the CC-by-SA license is explicitly mentioned. \$\endgroup\$
    – user12166
    May 27, 2015 at 21:04

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