Unlike many other art sites, e621.net has a tagging policy called "Tag What You See" (aka: "TWYS"). With very few exceptions, TWYS says that all tags on a post must be directly verifiable within the post itself. Example: a solo picture of what APPEARS to be a male character will be tagged "male". Even if the character was defined as "female" on other sites by the artist or character owner themselves, the picture would still need to be tagged "male" on e621, because of the TWYS policy.

This may seem unusual and even insensitive, but please read on to understand why the site functions this way.

Most artists and character owners are used to using websites where they can build their own personal collection of artwork and have direct control over it. This allows them, to an extent, to have control over how the artwork is presented and what additional information should accompany the artwork, if any. They often use the site's own tagging/keyword system to relay that additional information. For example, if a picture contains a fully clothed character that appears to be female, the artist may add "herm" as a tag on the post to clue people in that the character is actually a herm instead of a female. On those sites, this is fine; if the artist wants to draw things in a way that they look like something else, that's entirely their own creative decision to do so.

However, this is NOT the intended purpose of tags on e621.net.

E621's tagging system is intended to relay virtually NO ADDITIONAL INFORMATION or context about an image. Therefore, for every post on the site, it can be assumed that e621's tagging system is actually saying "this post appears to contain X" rather than "this post definitely contains X".

The very fact that e621's policy is "Tag What You See" INTRINSICALLY means that all tags on a post are only claims as to what's visible in an image, not what "actually is" in an image. Claiming what "actually is" in an image is often far more subjective than just saying what an image appears to contain, so we use the less-subjective method of TWYS.

• TWYS's end-goal is to make sure that when you search for something, you find only posts where you can actually see what you're searching for in the picture. Think about it: if you search for "balloons" on Google's Image Search, you expect it to display pictures that contain balloons, cause why should it show anything other than what you're searching for? Likewise, on e621.net, if you search for "herm", we want to make sure that the results presented to you are ones that actually appear to contain herms; we want to make sure you find exactly what you're searching for.

• TWYS is also crucial for ensuring that a user's tag blacklist removes any posts that appear to contain content that they don't want to see. Likewise, it should also NOT remove any posts that contain content they DO want to see. If a user blacklists the tag "herm", then no posts that are tagged "herm" would be displayed to the user, so it's critical that posts that contain characters that look like herms are tagged as such. On the other hand, if a post does NOT appear to contain anything that looks like a herm, those are posts that should NOT be filtered by the user's blacklist; if the character doesn't look like a herm, then the user might be fine with seeing the picture.

• Like several other sites, e621.net allows any registered user to modify the tags on a post. As a result, users who may not be familiar with a character's "default" gender (as defined by the character owner) will end up tagging the post with what the image looks like to THEM. If the image looks like it contains a male character, then they'll tag the picture with "male". Currently, this CAN NOT be prevented while still allowing all registered users to edit tags on posts. A future version of the site may allow tags to be individually "locked" on posts, but this is not possible at the moment.

• Sometimes, the original source webpage of an image (e.g. the artist's website) will be deleted or otherwise disappear, along with any "extra" information that the source was originally providing. If this happened, and e621.net did not follow TWYS, this would mean the tags on the post on e621.net would then be making claims as to what the post contains, but without having any external source to back up those claims. Since it's impossible for us to track when source pages get deleted or edited, using a source page to define what the tags should be on a post on e621 is problematic.

• Sometimes, what an artist claims their artwork contains is not what it APPEARS to contain. Example: Sometimes, artists will draw characters in such a way that they appear to be children, but the artist may tell you that the characters are NOT children. There's nothing wrong with that, the physical appearance of the characters is completely up to the artist that's drawing them. However, if these same characters are also depicted in a sexually explicit scenario, now you've got a situation where the artwork depicts what appears to be child porn, which is content that many people want to avoid seeing (they're depending on their Tag Blacklist to make sure such content is never displayed to them). On e621, such artwork would get the tag "young" to specify that it contains characters that appear to be underage, and "TWYS" mandates that it keeps that tag no matter what outside sources claim.

• Sometimes users are just going to disagree over what is "seen" in a post or not. This is simply an expected consequence of having a TWYS policy. These situations will often need intervention from an administrator in order to resolve.

• Gender tags (male, female, herm, etc) are typically at the heart of most TWYS debates. The reasons for this are numerous, but it boils down to A) artists drawing characters in ways that make it difficult to determine gender, and B) characters designed in such a way that they can easily appear to be either one gender or another (e.g. a herm wearing clothes typically looks just female). Again, there's nothing "wrong" with doing this, but it undoubtedly leads to confusion and people getting the wrong ideas if the artwork is ever viewed by itself. Again, e621 currently is interested only in a character's APPARENT gender, not their DEFINED gender. But sometimes even the apparent gender isn't obvious; in these cases, an administrator will need to make the final decision.