Do not watch Korra first - you will miss out on a lot of really funny references, and some really important background lore.
Yes. Watch ATLA first.
The problem with the last thread was that there were so many official and unofficial leaks. And not everyone can watch it "legally" at the same time.
If a show is big enough IE breaking bad/game of thrones it does mean more posters and thus more people who spoil intentionally or unintentionally
Especially if you have casual posters who don't give 2 fucks about spoiler tags or reading OPs
I agree with Okimaru on this one. Put the rules explicitly in the OP, and if people don't follow them, they get bodied. Simple.
There's no point in a real time discussion thread if we have to wait for everyone to watch something before we can talk plainly about it.