How should a reviewer flag a link-only answer? Hint, the answer is in the title.
However... whilst it is obvious (to most people) which flags apply to which answers - when those answers are really just comments and those answers that are just gibberish - I've never totally and fully understood the subtle difference between Not an answer and Low quality answer, with respect to the queues and the flags that the moderators see. This following post goes some way to explaining the difference.
This is copied verbatim from Please don't flag link-only answers as Very Low Quality
Lately I notice that many link-only (or link-mainly) answers are being flagged as Very Low Quality, so I am taking to meta to ask y'all to use the Not An Answer flag for link-only answer (LOA) posts instead.
I realise that the phrase "very low quality" is incredibly vague and open to endless interpretation, but the flag called Very Low Quality is only to be used for posts which are incoherent and not salvageable by editing.
Now, it's true that most of the posts we consider Not An Answer, such as answers thanking other answers, answers that say "I have the same problem; have you solved it yet?" and so on, are not salvageable by editing.
But there is one category of Not An Answer post that is fairly likely to be salvageable by editing, and that is link-only answers. Many new users, when prompted by a comment, will go ahead and expand their answer to include details from a link, and other users might be able and willing to edit such posts into shape themselves (I do it pretty frequently). It's not always appropriate to edit link-only answers (for instance, there may be copyright issues if we reproduce material from outside sources) but quite often it is, and editing might sometimes even make them good, upvoteable answers.
Now, you may well be thinking at this point that I'm being pedantic. Who cares what the flag is called as long as the post gets the correct treatment, right? The reason I care a lot about this is that the Very Low Quality flag has a really interesting "feature", which is that any action, except deletion, that resolves such a flag cast on an answer as helpful, will automatically cast a downvote on that answer. And for some reason, editing a post flagged Very Low Quality resolves that flag as helpful (even though the flag is supposed to be raised on posts that are not salvageable by editing) (this includes when the author edits) (this isn't the case for Not An Answer flags, by the way). So on those not-infrequent occasions when I find an answer flagged Very Low Quality (link-only or not) that I want to fix by editing, I have to do one of these things to avoid it being automatically downvoted:
- delete the post (resolves the flag as helpful), undelete it and edit it (if it was flaggable)
- decline the flag, and then edit the post (if the answer wasn't flaggable at all in my opinion)
I don't mind doing that, but, sometimes I forget to do it and edit first and the post gets downvoted. Ugh. Or someone else edits the post first (probably the author, poor soul), and it gets downvoted. Ugh. Or another mod dismisses the flag as helpful without deleting it because, although it's relying quite heavily on a link (or for some other reason was understandably flagged) it's actually not a link-only answer* (or otherwise deleteable), and it gets downvoted. Ugh. Nothing removes those downvotes!
In conclusion, please flag link-only answers as Not An Answer (unless you can fix them yourself or the author has indicated that they will do so imminently).
Why is a link-only answer not an answer? See this Meta Stack Exchange post Your answer is in another castle: when is an answer not an answer? (ironically I'm relying totally on that link...)
*When is a link-only answer not Not An Answer, and what is a link-only answer anyway?
A link-only answer is one that is not useful at all without the link. Sometimes answers that are useful without the link(s) they contain are flagged, but should not be. For example, an answer that gives a specific, relevant recommendation, even if it's very short, and includes a link that gives a step-by-step procedure to follow that recommendation, is not a link-only answer, because it's still useful without the link. Such answers can very often be improved, of course, by adding some version of the step-by-step procedure.
There are very rare occasions when a link-only answer is an answer and should not be flagged. Sometimes, the question asks for something which cannot practically be included in the post. For example:
I need a driver for this thingy I have
There is a driver for your thingy
[in this repository](URL)
Well, some installation instructions would be good, but we can't put the driver itself in the post, so this type of answer should not generally be flagged or deleted (commenting or editing or downvoting may be appropriate though).