What is the appropriate action to take when a user copies-and-pastes an old answer as a new one to a different question?

Question

Today I ran into this nearly 700-word answer and remembered it as being a duplicate of this answer by the same user. This type of duplication doesn't seem to be helpful and may sometimes be counterproductive (eg: I assume it negatively affects searches). Recommending that the answer be deleted seems incorrect as none of the available options are applicable. What is the appropriate action?

I do not feel that the questions are duplicates.

Note: In this specific case I think the answer is not a great fit for the second question, but let's assume that is not the case for the sake of this question.

Answer 1

I agree that straight duplication of content does not help anybody, not even the OP because they lose all the context of the original answer (comment threads, vote count, etc), in addition to gumming up the search algorithms, misrepresenting votes counts, etc.

Is it possible to simplify the situation into four broad categories?

1. A duplicate answer indicates that the question should be closed as dup.

2. Question is unique and a straight duplicate answer is appropriate. The answer should be edited to be a link to the old answer with a minimal amount of context for people who don't click the link.

3. Question is unique and a straight duplicate answer is almost appropriate. The answer should be edited to be more on-topic for the question (possibly still with a link to the old answer).

4. Question is unique and a straight duplicate answer is not appropriate. The answer should be deleted.

I'm not sure what a good, respectful, procedure would be for differentiating between 2., 3. and 4. in practice. Maybe leave a comment, come back in a few days and if the answerer has not responded then make an edit in line with either 2. or 3., or recommend deletion?

Answer 2

I once looked for a solution to a problem and found various Unix StackExchange, SuperUser and StackOverflow answers to variants of the question, or straight-out the same question. To assist future googlers, I posted the answer to four or five questions, saying something like "I answered this here before [link]: [citation]", editing slightly depending on context.

To me this was the best solution since:

• The questions were so old, they should have been moved but the other StackExchange site didn't exist yet back then. No need to move/merge the threads cross-site now.
• Not all questions were exact duplicates so they shouldn't be merged anyway.
• Future readers will see the solution, no matter which variant of the question they happen to find.
• Citing the whole answer prevents link rot.

On the down side, content duplication. But it was linked and the citation part was a citation, so it wasn't spamming the site to harvest reputation either.