This - the # wasn't a random choice for slack. And there's no shame in that.
And for those not familiar with IRC, the association of "#" with Twitter hashtags says "communication" too.
And for those not familiar with early Twitter, the hashtag was not a feature of the platform, but a shorthand way to indicate a topic. This of course was recognized and formalized by Twitter soon after, but I find it fascinating that it was a feature essentially developed by the users and more simply recognized by the platform later.
> a shorthand way to indicate a topic
And I imagine it was also inspired by IRC channels.
100% slack is essentially evolved irc.
The part I quoted was about Twitter, not Slack. Slack's relation to IRC was already mentioned. Essentially, my comment was "Not just Slack, Twitter too was inspired by IRC."
I'd bet that quite a lot of early Twitter users were also IRC users.