A few days ago, I created the tags blue_heart, orange_heart, etc. and populated them. Recently, the most used among these was the one of blue color, with about 70 or 90 posts. However, today or yesterday, they got deleted.
I'd like to know why. I can think of some good arguments and even counterarguments myself, yet I'd like to see what other people have to say about this small project.
Since heart is so huge, with more than 23 thousand posts (the limit of any search is 1000, apparently, far higher than the human patience to see multiple pages with the same subject), I think breaking it down by the color of each symbol is worthwhile to better control which images are found. Except red_heart and probably pink_heart, which are the most common colors; all the others ("green heart", "white heart", etc.) are comparatively rare exceptions.
If, on the other hand, creating these color-specific tags was a bad idea, even then I don't think deleting them all would be the best immediate decision, simply because we lost some information in the process. At the very least, the new tags could be merged to heart; but unfortunately they weren't.
Since I can't show the full lists of formerly tagged posts now, here are two simple examples with black hearts:
Well, it seems purple_heart, green_heart, black_heart and white_heart were tags already in use for characters. Just the fact that you went ahead and created new tags for these characters and moved their posts without discussing it here first is reason enough for someone to delete your tags and undo any harmful changes you might have caused.
Also, whether these new heart color tags are really useful or not is something that has to be discussed and decided here first. We don't have tags for every single color or property an object might have. If people don't need such tags, then they're just annoying clutter.
Finally, I hope you don't mind me taking this opportunity to express my opinion about your recent activities in general: It seems to me you try too hard to fix things that aren't really broken. The vast majority of tags (if not all) work pretty damn well and that's because Danbooru's community has discussed, defined, refined and used most of these tags over a period of years. Users have come to understand them and use them appropriately most of the time, and with the exception of new copyrights and their characters, there's rarely the need for a new tag. Don't get me wrong though, there's always room for improvement, and it's great that you are so enthusiastic about improving things, but when you try to do it single-handedly without informing anyone and without having an appropriate discussion first, you might end up causing more harm than good, even if you're actually right and your ideas are good.