This post is outdated but still worth a read in my opinion. The up to date version is linked at the bottom of this post.
Problem:
Small breasts are not treated in the same way as large breasts, huge breasts and gigantic breasts.
Every distinct breast size except small_breasts and flat_chest implicates breasts:
This is not very consistent.
It becomes even clearer when we take a look at the wiki page on small_breasts which warns: "However, do not use the breasts tag in conjunction with this tag unless they meet the definition of that tag, i.e. they are noticeable or the focus of the image: e.g. partially or fully exposed breasts, breast comparison, breast measuring, breast envy, etc."
The bigger breast sizes do not have this restriction.
Okay, time to give an example that puts everything together.
For this example let's assume we want to create a post with the following tags: 1girl, cum_on_breasts, nude, small_breasts
After the implicated tags have been added the resulting tags are: 1girl, breasts, cum, cum_on_breasts, nude, small_breasts
Now we have two new tags namely cum and ... oh well ... breasts. Apparently small breasts become the focus of the image when they have cum on them.
Joking aside, this behavior is caused by those kind of tags which describe appearances connected with breasts.
Here are two of them implicating breasts:
Solution:
Create implication: small_breasts -> breasts (link to implication)
Remaining issue I:
The breasts tag is used as both a generalization (above scenario) and a specialization (distinct breast size: "average medium breasts").
If a Danbooru user wants to search for media containing average medium sized breasts, he will have to use the blacklist or create a query with exclusions (e.g. breasts -flat_chest -small_breasts -large_breasts -huge_breasts -gigantic_breasts).
But this would also exclude posts with constellations like: multiple_girls, breasts, large_breasts : (
Creating an average_breasts medium_breasts tag would make this easier.
Remaining issue II:
I'm referring to the above note on flat_chest -> breasts.
Treating a flat chest as breasts would eliminate unnecessary special solutions like flat_chest_grab.
Furthermore, one would be able to tag cum_on_breasts together with flat_chest without having to revert to more general tags like cum_on_upper_body that do not implicate breasts.
What's your take on this? : )
Notes:
[1] I am aware that a flat chest is in fact a colloquial description of undeveloped breasts. They are barley noticeable and therefore not considered breasts on Danbooru.
The Wiki page on flat_chest states: "The flat chest tag is mutually exclusive to the breasts tag, i.e. don't tag both unless another character in the picture meets the criteria for the breasts tag."
But this doesn't prevent complicated discussions on whether to use breast_grab or flat_chest_grab for a flat chest that is being grabbed.
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Update 1: refer to forum #114820 (outdated)
Update 2: refer to forum #114847 (partly up to date)
Update 3: refer to forum #116330 (up to date)
Update 4: refer to forum #116365 (up to date)