It's not the first time that this happens in this site but, since there is no Meta post inviting to discuss it (or at least I haven't seen it), I decided to write one. Lately, specially on answers, I have noticed a proliferation of downvotes without any comment to explain why. In general, I feel that this behaviour is not very constructive for the site for the reasons explained in this Meta question: explaining why an answer in being downvoted encourage the poster to improve that answer. It can even encourage that user to write better answars in the future. Of course there can be some exceptions to this "rule". For instance, if one finds an answer that is spam in a very evident way, it's no worth writing a comment to say "we don't want spam in this site". I would like to have your opinion about that and see if you think we should/could do something to discourage that practice.
[In addition to this, speaking specifically about answers and always in relative terms, I have the impression that, lately, the amount of downvotes is relatively high whith respect to the total amount of upvotes on answers. I sometimes wonder: we are really doing so bad in comparison to the past? I know this is another subject that maybe should to be asked in another question. I don't do it because I'm not sure if this is really that way or it's only a subjective impression.]