I would say the entire Ken Shirriff's blog site is amazing. A lot of very interesting system's articles there.

I think Slack is better suited for information oriented conversation

Why?

Maybe because there are no threads in discord. If you want to reply to someone on discord you can only use 'cite' or @. And if there alot of people in a channel its hard to follow a discussion.

Isn't it possible to send them a DM?

And then nobody else benefits from the discussion