How best to deal with link only posts?

Question

I notice a common anti-pattern is that a user, possibly posting for the first time, posts an answer along the lines of:

The answer is in this link.

where the link may or may not be to their own blog - for argument's sake let's assume it isn't (or at least the affiliation was declared). The standard comment against this is along the lines of:

While this may theoretically answer the question, we prefer inclusion of the essential parts of the answer here, and to provide the link for reference. See answer for general guidelines.

These posts are frequently flagged. The question is, as moderator, what to do? The link may be useful (for the time being at least) so deleting seems harsh. I think the correct tool is down-voting to push the post down the running order.

Should we:

Just delete the post?

Delete post and ask user to expand and it will considered for undeletion?

Everybody down-votes rather than flagging?

Everybody down-votes with comment to explain why rather than flagging?

Down-vote AND flag?

Just leave a moderator message?

Convert to comment?

Answer 1

Changing answer into comment would be the best option.

If we will down vote it and later on user edit's or improve his answer then it's most unlikely that people who down voted it will come back to remove there down vote on this specific answer.

I personally don't believe in down voting or if it is any constructive.