This is about exactly the thing it says on top: please do not say openly and directly in comments, the things in an answer which were spoiler-tagged.
There are good reasons for this:
1. It makes the puzzle harder to solve for other people. When you say "X is a good attempt" or "Y is really close, think a bit more about the clues" you spoil the novelty for latecomers, whose thoughts will focus on the subject you restate - consider don't think of the pink elephant as an analogous of why this is a problem.
2. It is rude to the answerer (whether or not they think so). They took the time to learn about, and then put in spoiler mark-up. Whyever they did so, you've changed that choice for them, without their input and quite possibly to their detriment.
3. It ruins the puzzle for the future visitors. Similarly to point 1, seeing other answers or even the correct answer before being able to think through the puzzle, takes away the challenge and much of the fun. Anybody can read the current proposals by hovering; nobody can unread them by not hovering, if your comment said it too.
For people who aren't familiar with spoiler mark-up, this helpful Q&A will do well. For those who are, but ignore it, please be careful!