Down voting without reason is worthless in many cases as the user may not understand what the problem is. Leaving a anonymous comment is beneficial to the SO community as it helps with the quality of questions in general.
Going further, perhaps a small floating UI control could be added, that would be required to be filled out by the down-voting user:
[ ] Not in Q&A format (1) *F*
[ ] Not applicable to this Q&A forum
[x] Unclear (3)
[ ] Other
How it would be used:
Other would require an anonymous comment to be added, either to the comment list or to the UI control of the question in question. Maybe adding to the standard down-voting reasons would be allowed by users who have a rep above some value.
- Counters at the end of the standard reasons would indicate that other users agree.
- This control would be read-only to everyone except those who down-voted, and would not be visible at all if no down-vote had occurred.
- Those who don't down-vote would only see the applicable reasons that have been selected by others.
- Upon revisiting the page, the down-voter would only see the applicable reasons that have been selected by others along with checkboxes showing what that down-voter checked. A handle at the bottom of this list would allow that down-voter to see the rest of the possible reasons in the case they wanted to change their reason.
- Down-voting would not be applied until the down-voter checked off at least one box.
- Unchecking all of the boxes that the down-voter checked would remove the down-vote(s) by that down-voter.
- If more than one were checked, it could be that multiple down-votes could be applied.
One other thing could be that if there are users who disagree with the reason, it might be possible to flag it (what the
*F* is trying to represent). If enough people flag it, it could remove the reason. No one would be able to see that it was flagged except for the flagger. It would not affect the down-voter's selection, but it would decrement the count to a minimum of 0. An N:1 flag:reason ratio would be used to decrement the count, where N is TBD.
Using this UI control or something similar would require only one additional click unless
Other was used, in which case some additional typing would be required. No one would know who casted these down-votes. However, the feedback given to the questioner would immensely helpful (especially new ones).