It was suggested that link-only answers should be automatically deleted, instead of requiring flagging or delete votes. Although I agree that it could work in many cases, there may be false positives, and it seems that request will be eventually declined.
So here is an alternative: what if we require an answer to consist of at least 50% of non-link content, at the time of posting? So, if I try to post an answer such as:
This might help you:
[Link text is 26 characters](http://example.com)
I could get a warning like this:
Your answer consists mostly of a link. While this may theoretically answer the question, it would be preferable to include the essential parts of the answer here, and provide the link for reference.
Maybe it's not even necessary to block the posting completely, we could have a "post anyway" button. The warning itself could be enough to discourage users from posting link-only answers.