Plagiarism is a tricky subject, and an area where the site must proceed carefully. By the nature of Stack Exchange, everything on it is explicitly
public domain re-usable(see Brad's note below). If that was not the case, what good would the site be? In the quoted example the answerer behaved in an eggregiously boorish manner, granted, by not crediting the source; but can we truly say that it was malicious, or even intentionally deceptive rather than merely uninformed and hasty?
In the example provided the answerer DID post a solution to the question, promptly, and received rep as a reward. The knowledge of where to look to find an answer is in fact one of the skill sets that this site offers, and rewards with rep. Who here can state that they have never referred to an online manual, a book, another question on this site, or another technology forum in building an answer? Did you put quote marks around everything you discovered in such a look up? Of course not, because much of that is fair use, and required interpretation before being apropos to the answer you built. My point is that we are comparing two extremes, between which is a large very gray area. In attempting to regulate the extremes we should tread carefully in the gray area, to not be seen as heavy handed.
Expanding a bit based on my conversation below:
I suggest that in this area it is important:
- To have consensus, not just majority, agreement on how to proceed;
- That specific character counts, possibly with different weighting of between code blocs and text, be set for identifying content as being "clearly plagiarized", "questionable, needs review", and "clear"; and
- That very explicit guidelines be set for how appointed "plagiarism-moderators" should make judgements on "questionable" posts.
- That the qualifications for being a "plagiarism-moderator" MIGHT not be the same as being a moderator in general for a site, and should be discussed as well.
And finally, to emphasize a point made by Servy: "... because really sorting out any non-trivial cases of plagiarism is very hard ....", I recommend cautioun while the site moves forward.