Ah, this explains why those threads got un-stickied. For one sticky thread to rule them all. I am OK with that.

I am not really sure if it is such a good idea to post a seperate thread for each flag, grave, hat, etc. I recently posted a few dozens of flags, I certainly would not want to create dozens of threads.

hh.unit22.org seems like a good alternative, but I am not really motivated to package each single flag into a HWP archive just to make the web interface happy, this seems to be like crazy much work.

Some complaints about the rules:

• Your content meets the Hedgewars style guide-lines and doesn't look bland or offensive.

If you would enforce this rule consequently, there would be not much additions to Hedgewars. This is because anything can be considered “offensive” by someone. There are probably even people who think those references to Christianity (crosses graves, Chrismas theme, Halloween theme, etc.) are offensive since *their* religion does not appear, lol. Whatever, I don’t care. Some people are offended by really weird things, most of the time for completely arbitrary reasons. Also, feeling offended is a personal choice. If someone is offended, it’s because they want to be offended.
In other words: This rule is way to vague, arbitrary, would exclude extremely much stuff when enforced consequently.

• Your creation must not contain any copyrighted content of others and it must be available under a license that permits inclusion in the game and is compatible with the license used by hedgewars (GPL2)

This rule explplicitly forbids to post anything not created by the poster, even if there are no licensing issues, because it is so easy for something to fall under copyright in so many states. Copyright does not magically disappear when you slap a license on it, no matter how liberal, it is merely the copyright holder granting permissions. In short: If I post something under the WTFPL from someone else, I have broken this rule.

• It helps if you specifically state your permission in the thread(s) of your creations. Otherwise we might have to ask you at a later time (when you might or might not be available)

Sigh. We live in a permission society.

Since you insisted: Everything which is created by me and posted on www.hedgewars.org can be considered to be under WTFPL.

Edit: Oh, I would suggest to standarize those “tags” you mentioned (not just an example). I propose the following thread naming scheme:

• The “tags” are always written at the beginning of the thread title.
• There can be one or more tags per thread
• Possible tags denoting content are:
  • “[Voice]” for voice packs
  • “[Map]” for image maps
  • “[Hat]” for hats
  • “[Fort]” for forts
  • “[Grave]” for graves
  • “[FTheme]” for full themes (standalone themes)
  • “[BTheme]” for background themes (non-standalone themes, work only together with map)
  • “[HMap]” for hand-drawn maps
  • “[Campaign]” for campaigns
  • “[Mission]” for missions (mutliplayer or singleplayer)
  • “[SMission]” for missions (singleplayer)
  • “[MMission]” for missions (multiplayer)
  • “[MScript]” for multiplayer scripts (excludes missions)
  • “[Script]” for any Lua script (generic tag)
  • “[WScheme]” for weapon schemes
  • “[GScheme]” for game schemes
  • “[Scheme]” is a shortcut for “[WScheme] [GScheme]”
• A couple of “modifier tags” modify the meaning of the thread, usually written at the beginning:
  • “[Col]” is a modifier which denotes collections. Use this as the first tag if you have multiple items of the same kind (i.e. for a flag collection, use “[Col] [Flag]”). Can also be used for “collection threads”.
  • “[Ofc]” denotes modifications of official Hedgewars resources, possibly intended to be included for upstream
  • “[WIP]” when it is still a work in progress (unfinished)

Examples:

• “[Fort] MyAwesomeCastle_v1” — A fort with name “MyAwesomeCastle_v1”
• “[Map] MyAwesomeMap_v4” — a map with name “MyAwesomeMap_v4”
• “[BTheme] [Map] Hoglands_v1” — Thread with background theme and map with name “Hoglands_v1”
• “[Col] [Grave] Hedgehoglover’s Grave Pack” — Thread with multiple graves
• “[Ofc] [Mission] Better RCPlane mission” — Thread contains a modification of the RCPlane Challenge

Note that this is only an “unofficial” convention I suggested. I first want to hear what others think about it.

EDIT2:

Ugh: I noticed that by using tags, it doesn’t become much better. Well, it’s better than nothing but not the best solution.
That’s because Hedgewars has quite a lot of content types now.
The best solution would be to open subforums for every content type, at least for the most important ones.

I said "create a thread for your creation(s)" -- with the optional plural to indicate that one ofc can make one thread for a bunch of flags, hats, etc. ^^

I agree on the topic of subforums, but I couldn't be bothered to create them yet - partly because forum activity is so low at this time.

I kept the tags simple and rough, because - as you noticed in your second edit - making a more detailed and complicated tag system like that would end up adding more to the mess than it would help.

Yes. But that's kinda the point. The selection process and what is considered offensive or not will often be vague, arbitrary and cannot be enforced consistently.
We're not robots, we're human beings and we'll have to make decisions based on opinions.
Sometimes those might be weird, sometimes they might change, sometimes we might just forget about stuff for a while.

We're humans so our judgments are those of humans.
We will not strive for perfect rules and flawless fairness - as this is not possible for humans, especially not when it comes to opinions on art.

If we had strict rules that were the exact requirements, then there would still be cases that would meet those rules, but still clash with our artistic expectations in context with hedgewars.
Then we would have to either force-accept or reject (which would feel really unfair to either other artists or the one getting rejected) and would have to create more and more rules to make sure that won't happen again.
(new rule: some minimum contrast required, new rule: sufficiently distinguishable from game items, new rule: water color must not match background color, new rule: don't focus heavily on memes, new rule: don't make feces the main feature, new rule: no seizure inducing flashing, etc., etc., etc.)

So yeah, it's a lose definition by design as it's impossible for us to exactly tell anybody what is needed to get content included.
I'll try to clarify that a little in the OP.

"Your creation must not contain any copyrighted content of others" - Maybe I should reword or reformatted - because the emphasis is on -copyrighted-. Ofc it's okay to contain content that has been permitted to be used (e.g. "copyleft").

What about free reuse licenses with attribution CC-BY, CC-BY-SA?

CC BY and CC BY-SA are OK, because they are considered to be licenses for free cultural works. Just make sure you understand the licenses (i.e. don't misattribute and in the case of SA, don't replace the license).

As Hedgewars is a free software project, free cultural works are very welcome. In fact, 100% of the media files in Hedgewars qualify as free cultural works .