It's not though; all topics are permanent and searchable. So it's the best of both worlds. Have you ever tried searching chatrooms and 100+ channels? Excruciating.

I have used search in slack/discord/telegram and found it's super fast and fairly reliable. I can often see references to the same error messages or bring up the topic I'm interested in.

Discourse has the advantage that it is indexable by Google which is a big one, but I don't share the frustrations that many here talk about.

IM has always felt faster and more responsive than forums ever did. I used to be a huge forum user and I remember posting questions and having to wait at least a day to get to an answer while on IMs I have often found people start to help out immediately and provide their best guess even when they don't have the full answer.

While forums felt too formal and if you didn't post a well researched and correct question, your post would immediately be locked/flamed/sunk down.