My opinion, if you *REALLY* wanted to flag that as low quality, you could just use a custom reason and put "Link only answer".

I'ld drop a comment first though, saying something like "Link only answers are discouraged.  Can you please post some of the content here?" and link to the post on MSO about [link-rot](http://meta.stackoverflow.com/questions/252306/why-is-this-link-only-answer-disputed/252454#252454).