There are I think two useful features things like Slack and Discord have brought to the table. 1. Pinned messages. Yes, to an extent Channel topics can serve t

There are I think two useful features things like Slack and Discord have brought to the table. 1. Pinned messages. Yes, to an extent Channel topics can serve this way, but the limited space in IRC leads to "Use !jabberbot help for a list of commands, and !jabberbot faq so we don't ban you for asking the same thing for the 40th time." Slack and Discord suffer from people who don't read pinned messages but it can at least help deflect repeat stuff. 2. Threading. In some contexts, it makes sense to take a follow-up loosely "private" in the sense of not messaging to everyone else in the channel. Other than these IRC is superior in basically every other way.