This question: Most space-efficient freeware file compressor? got 6 downvotes, but I don't understand what is so terribly bad about it. It asks for a good file compressor with certain criteria listed in the question. As far as I understand, it is a perfectly good question.
It doesn't ask for a good file compressor. It is specifically asking for the best, or in the case of this question the most efficient.
That doesn't give answers much room to move. I would have posted 7-zip as an answer. I find it to be a great file compression utility that otherwise fits every point brought up in the question except that I don't, and probably never will, know if it is the most space efficient.
If the question had been worded something more like: "Please recommend a file compression utility with consistently high levels of compression on filetypes x, y and z" I think this question would have not been hit so hard with the downvote hammer.
This question was downvoted, because I have asked for best tool. I can't understand why it is so wrong, because I'm looking for best tool and I'm asking for recommendations. The best tool would be selected by comparison with specific criteria.
I will check all proposition myself on sample files, equals for all tools and accept the best (with smallest archive).
Users visits this question and downvote without any comments or advice what is wrong.