Q:

Autoconvert site-internal-link-only answers to comments

When an answer consisting solely of a link to elsewhere in the Stack Exchange universe is posted, it should be converted to a comment prefixed with "See: ".  Perhaps this could be widened to cover any single-link answer.
Some sort of rubric, perhaps

Your answer consists solely of a
  hyperlink, and will be posted as a
  comment unless you add further
  details.

could appear when the answer is being composed.

A:

My own inclination is, if the answer is solely a link to another Stack Overflow page (or same-site on the Stack Exchange network) the answerer should be prompted to post a full answer, explaining how that answer is applicable or may be amended/adapted to answer this question, or consider flagging the question as a possible duplicate of that question.
If the answer is a link to another website, outside of the Stack Exchange network, then I sincerely think that the answer should not be accepted for posting to the site, possibly until it's been reviewed and 'accepted' by a community moderator/>10K user. An explanatory note should be presented to the person trying to answer, but a link is not, nor should be considered, in most cases an answer.

A:

Now completed per the answer provided at
Answer appears automatically converted as a comment

I posted an answer (pointing to another question already asked) but when I hit submit, I saw my answer appear as a comment to the question instead.

