There are questions on our site (for example here and here) with no answer but a useful comment that links to elsewhere. There are lots of discussion on this Meta.SE question: Are answers that just contain links elsewhere really “good answers”? or this one: Your answer is in another castle: when is an answer not an answer?. But these are mainly about link-only answers.
OTOH, there is this question: What if I answer a question in a comment? and this discussion on our own meta: How can we get people to provide answers instead of comments. I also remember that Robert Cartaino said somewhere (I paraphrase)
When finally people find this site, we don't want to send them to find their answers elsewhere. Links are good but they should be supplementary.
So, what should we do in these situations? Should we:
- Ask/encourage the commenter to expand their comment into an answer (I get this from combining/summarizing the above)
- Leave the question as is and do nothing and hope that someone else will provide an answer at some point
- Something else