This is related to this question from Diago last year. I have seen a lot of answers with either a link only, or a link with a short description copy/pasted from the developer's website.
Personally I think this is a bad practice, as it gives the Asker the impression that the person posting the answer has used the product and is endorsing when they likely have not actually used it and just found it via a Google search. If they had used it why would they not post their own quick writeup?
So my question is, is it OK to downvote these answers? As a followup, if it is OK, what should we do about users who repeatedly do this? I have seen a couple the past few weeks that seem to make a habit of it.