Unfortunately, that's exactly what that site is for...

There are a list of DNP (Do not post) unless the admin know your still and or that the credit is post, your art might get past the mods.

its a site thats been around for many years. its like a depository of mostly adult furry art.No one profits off of it really as far as I can tell.But as you say no one ever really asks permission to post things there. It is rude that way.Its also a potential problem if youre trying to monotise the artwork online behind paywalls or such. Most artists don`t fight it.So There is a do not post list though that is sort of enforcedme even embrace it as another place to put their art.Treating it as a search engine for any type of furry art youd want to see and link it back to their own galleries.
There is a DoNOtPost list though that is sort of enforced.

Its kind of a matter of course that people swipe stuff to reupload it on E6. That said, its part of the rules iirc that you have to link back to the original author, if that makes ya feel better.

I've seen a bunch of my art posted there, but it's properly credited to me, and most of it is just FA reposts, so I don't have a problem with it. It also has a robust tag and filter system, so after you configure your eye bleach filters, browsing by keywords can become an interesting exploration.

Sadly many think it funny to say "it's easier to apologize than ask."
It's not right, but I can't offer a solution either.

e621 tends to collect lots of stuff, not sure on the rules thay follow, if you wanted you stuff taken down try talking to them maybe? most of the art posted there tends to be lower quality posts, aka, tiny puctures, low rezalution pizilated or the like. Some folks use it as a start for looking for stuff.

Aye, there are times where people will ask before cross-posting to there, but once the first few images are there that rarely happens. Oddly, I hadn't noticed your art on there before, or I might have let you know about it in the past decade various folks have been posting your art to there. Any preference what gallery site they should link back to? I have a basic account there, so I could update them all with base gallery links if you'd like (multiple gallery links can be listed). Alternately, you can ask the staff to remove your art and put you on their Do Not Post list of artists. Up to you!

ignorance of the users on the internet, people just take what they want and think it's free to use for his/her own sites/galleries etc

As folks have mentioned e621 will take down art if requested and put you on s Do Not Post list. It's rather annoying that they don't ask permission in the first place, and, on the other hand, it's free publicity - brings you new fans. Another annoyance is when is when no one continues to post your art there....

Yeah, pretty much what everyone else said.

Send an email to the admins there and they will take it down, once they verify you really are you.

I'm not so much upset about the stuff being there as much that some one put it there to being with.

At least your art hasn't turned up on a commercially-sold CD of pirated works, as my friend's did. :3

personally i like the idea, of non-ownership. but with it the idea, of not for profit.
but then i realize, what a lot of people create is what they live off of,
and i don't really have any good answers to the conflict between the two.

like most things in life, its up to the integrity of the person who finds it.
laws only exist because so many people seem to lack this.

i like pinterest. i like that i can right click on something and make it part of what
appears randomly on my computer's screen when i'm not doing something else.

i would never knowingly pay for something from someone who stole it,
or sell anything i didn't create myself.

i just don't have good answers for a world that makes things have to be about money.
it surrounds me, but its not what lives inside me.

if i could live in a world where i could just make things,
and nothing had to cost anything, that is what would feel natural to me.

which i know to most people is probably just weird.
i mean i know there's cost in nature, just not in terms of symbolic value.

i've heard about that place, e-whatever it is, just never got around to looking for it.
same with redit, which i went to see and didn't see anything that interested me.

i like your coyote girls and most of your ideas from the first time we ever ran into each other.
the thing is, i'd still rather have in internet where this sort of thing can happen
then one that was completely controlled by economic interests to where it became just more television,
which is the last thing in hell that would be of any use or interest to me.

You didn't even know about e621 until now...?

Sir, you are a treasure. <3

Yeah, I'm so out of touch. Don't twitter, or text, or even have a personal digital device. Other than here and Deviant Art, don't have other social media sites to gallery my work. Did finally get my own web site up, but that was little more than a year ago.

Sad that people posted your art without permission.