alan-hn
At first I thought you meant twitter, I definitely wouldn't want my kids on twitter these days
null_investor
I've visiting communities like HN since I was less than 10, in BBS.
mepian
With such framing I'm tempted to say TikTok.
cpach
I’m an old, but if I was in that demographic I would probably launch a Discord space (or tenant or server or whatever they call it in Discord parlance).

Slack could be an alternative. Not sure if teens are used to that though? Perhaps Matrix could be another alternative, but the UX there can be quite confusing IMHO.

dotcoma
Some subreddits ?
solardev
Why can't the teenagers read the same things the adults do?
red-iron-pine
Discord. Maybe reddit.
elfbargpt
HN
Zambyte
A local library
hnthrow098767
hackclub non-trivial

I guess hn is suitable for teenagers as well.

admissionsguy
for example thestudentroom.co.uk
rpois
X
gaws
x = Discord
aaron695
[dead]
EKNOAES
[flagged]
infotainment
[flagged]