managed permissions, built in history (doesn't rely on you being connected to get a log of a conversation that happened when you were gone), great full text search, integrated rich content (posts, videos, images) which are also searchable in the same way, adding context to conversations, built-in system for notifying people, channels, and groups, with centralized options to tailor those notifications to yourself, a fully featured mobile application that synchronizes with the desktop app seamlessly.
Slack basically removes the requirement for you to have an IRC server, client, and a suite of IRC scripts and bots. It unifies the experience across the team, which, yes, does remove some levels of customization you would get from your personal IRC client, but in practice, it's been a highly productive work-chat tool.
I've basically replaced Dropbox as my source for important files, instead, putting them into a Slack channel. That way what ever made that file relevant is surrounded by the chat that necessitates the file.
It's not for everyone, and I don't think anyone would claim it should be, but if you work on a team, especially a distributed one, Slack brings a lot to the table "batteries included."
Do you still have your IRC logs from 15 years ago? That's a loaded question. I know some people do, but most people don't and most people don't need them.
We put things all over the place that include "what ifs" – what about files in dropbox, or emails in gmail?
Everything includes some level of trust and some level of acceptance of ephemerality or potential loss.
Personally, everything in Slack is work related, not personal, so it can go away, just like I could get fired, or quit, and never have access to it again. If there's something I want to keep, I'll keep it somewhere I believe is safe and permanent, that's up to me, not Slack, or the tools I use.
I also have a reasonable expectation that Slack would provide some sort of export/dump of data, similar to what twitpic did, or any other business does when they sunset. This doesn't always happen, and it's not fair to assume it would, but I trust Slack because they've done a very good job at being responsive to their customers' needs thus far.
The same thing that happens every time you change a piece of software or technology?
You find a new one to replace it. Import your slack backups on it (someone who asks the kind of question you ask surely has backups, right) and get rolling.
Slack basically removes the requirement for you to have an IRC server, client, and a suite of IRC scripts and bots. It unifies the experience across the team, which, yes, does remove some levels of customization you would get from your personal IRC client, but in practice, it's been a highly productive work-chat tool.
I've basically replaced Dropbox as my source for important files, instead, putting them into a Slack channel. That way what ever made that file relevant is surrounded by the chat that necessitates the file.
It's not for everyone, and I don't think anyone would claim it should be, but if you work on a team, especially a distributed one, Slack brings a lot to the table "batteries included."