There's a different feel for something like Reddit, where you know your messages will be on google next day and easily searchable, and Discord, where technically your messages are still a permanent record, but the difficulty for someone to do something like find everything you've chatted about is much higher with search engines out of the picture. Communities are communities but typically the discussions within them aren't 100% in a reddit-like thread style where each message is an attempt to add to the discussion. This feel means the vast majority of Discord users are participating in chat and talk, while Reddit HN etc. likely follow the 90-9-1 rule (90% are lurkers, 9% will reply, 1% will post original content).