I don't seem to get the error anymore. It could also be related to my newsfeed not being as active as it used to be so my own testing results could be skewed.
That said, I think we can consider this fixed.
I will try to reproduce the error.
A policy won't keep people from being trolls. You can enforce them yes, but that doesn't preemptively prevent trolling when the damage has already been done.
I would also rather opt for a system that lets an artist decide if they accept a tag that has been added by the community. Furthermore, if an inappropriate tag get's added too much give the artist the ability to block the tag itself from being added, either to a particular submission or to any submission in the artist's gallery to provide the artist with a tool to prevent mass-trolling.
Alternatively, if the system is set up for it, give the option to block the individual who has placed the tag -- I'm thinking like ask.fm: even if the question was asked anonymously you can still block the person having asked the question if they start getting on your nerves. Just so people don't get upset with "privacy concerns". The artist doesn't know who placed the tag (so no shaming) and the troll is blocked from placing inappropriate tags.
Another idea to this could be that if tags for a certain user get rejected too much they'll have their ability to place community tags revoked or put up for review (or both).
Or since promotes are handled like a "shout out" to other users, as in "broadcasting" that you like something in particular to raise attention a bullhorn could also convey that: http://fontawesome.io/icon/bullhorn/
Favs/Promotes already have a familiar feel to them in that the mechanic has been in use for years on other social media sites and the majority of users should feel right at home about how to use them.
As I pointed out earlier to cater to those uncomfortable with having their name in other user's notifications when having fav'd an artist's work (tho I have to wonder why it wasn't brought up before FN's inception on any other site) is to actually do have a setting that says "Notify other users that you fav'd their work? Yes/No" to at least give the feel of being more in control.
But if a user decides to hide favs in other user's notifications it should probably also not generate a notification at all, only raise the counter of total favs on the particular submission. As pointed out by others before anonymous notifications are pretty much useless and don't convey any informative value other than "someone likes your stuff but we're not telling who or what" and that's probably what's so confusing or jarring to most people. If we're not allowed to know who fav'd what, why even tell us about it at all?
The AUP doesn't exactly state where to draw the line.
All I can think of is that mature is nudity and clothed pinups maybe. And even then there should be clarification if i.e. a boner is still only mature or if it already counts as explicit.
Explicit would be anything that implies sexual acts taking or having taken place.
I'd also very much appreciate if there was some confirmation. It does work but it's rather confusing if there is no confirmation message whatsoever and you have to confirm it yourself by logging out, trying your old password and checking if it says "invalid password".
I think the best of both worlds would be a setting which allows users to choose if they want favorites to be private or not.
Promoting artwork feels more like a Twitter retweet to me, in that it shows up in your timeline like "Hey you guys, this is cool, check it out" and favorites being like "I (personally) like this".
Either way, as long as it's just for notifications who favs the artworks I uploaded to my gallery I don't really see an issue with it, but that's just me.
As I mentioned above, a per user setting of "Make my favs private" could be an option for those concerned about someone else being notified with your name attached to your faving habits. (Then again you could argue that faving "special interest" artworks already has the notion of the user uploading it and the user faving it sharing a common interest and there's not really all that much to be concerned about, e.g. kink shaming)
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