>Hard to define everything exactly in advance because it can be a fine line.
True, but I think that when you see it, it's usually pretty clear whether someone's just advertising for profit, or shilling his horse passion project as part of a discussion.
I for one would be against requiring permission in /qa/, because it adds extra friction and effort for people who might want to post something; and if something is borderline, it puts the responsibility on them. "If you weren't sure, you should've asked!". As a user, I know that I'd probably just not bother posting shit 99% of the time in an environment like this.
Rather, if something is borderline - not blatant advertising/spam, but still seems more malicious than a genuine part of a discussion - we can issue a warning, and that'll be our "please tone down the shilling" message. Followed by a Rule 10 ban only if they keep going.
While I get the idea behind that, I'm not sure if it's possible to fill a board with this kind of stuff. On /mlp/ there have been a few threads like that, from the Active Pony Projects one, nowadays TEMPO, the fan site thread to an extent, plus individual threads collecting stuff (I'm thinking mainly the gaming thread's pastebin). Threads seem like a more natural environment for that, than a dedicated board entirely for shilling.
ON THE OTHER HAND, maybe having a board just for "projects" where people can make dedicated threads for each project and post in them could actually be an interesting idea. Kinda like /vg/ but for horse project (and like 10,000x slower, kek). Wanna discuss, I dunno, Sweetiebot? Instead of starting a thread that will get 4 replies and die, find the Sweetiebot thread in the /projects/ board and post there. And instead of every Sweetiebot thread consisting of an OP asking "yo have you guys seen this awesome project" followerd by a couple of replies saying "lol they are doing jack shit", those posts are gonna be at the top of the persistent thread in /projects/, and any new posts will only really happen when someone has something new to post.
I dunno, it could easily become a mess, but I think it has potential to work if done right. BUT, it would also require a decent userbase to keep up - a ghost town board with threads for like six projects and the last post being someone posting an update half a year ago, won't really do much other than perpetuate a "dead board" reputation. So maybe something to consider if/when we successfully take off.
>Just seems a bit silly to me to make a rule specifically for Discord.
I think it makes sense, because this site is basically intended for refugees/crossposters from /mlp/, and on /mlp/ Discord links are very much allowed despite 4chan having the same "no advertising" rule.
Moreover, you have an explicit rule against EqG, despite the fact that "pony only" could ostensibly cover that. Why? Probably because /mlp/ allows EqG despite being a pony board, so you had to specify it explicitly to manage expectations. Same with Discord, in my opinion.
Discord is also a quite unique thing. Even IRC isn't anywhere near as bad (see OP screencap, I posted that specifically to point this out). Would you say people mentioning IRC channels should be bannable? If yes, I don't really agree with that. If no, then it's inconsistent with considering Discord "just part of the advertisement rule", because then IRC would also be part of that rule.