Slack offers markdown, message editing, emoji reactions (which I use the hell out of, one of my favorite features), large snippet sharing, link previews, in-app gif/youtube previews, don't need a logger for scrollback...
I love IRC, but the features don't compare. You might be able to implement some/most/all of the missing features, but they're not available out of the box.
I think the downvotes are because ircd != Slack. Setting up your own ircd is a whole other thing vs going to Slack.com and creating a Team. UI features, administration, it's all different. So we could have a whole conversation about whether irc is worth the effort... but now we've drifted far from the comment above, which is about lack of security features in Slack.
I think his point was that IRC, too, allows instant communication, and self-hosting would allow parent to enforce necessary security policies. Not that it is or isn't worth the effort.
Don't you get it? People are not willing to put up with older technology that works, because the UI design has fallen out of favor. People need something dumbed down, mobile friendly, with low barriers to entry, but most importantly of all: it has to be something everyone else is using. Because the most important proof is social proof. There is no place for your solution here /s
So none of the benefits that Slack brings over IRC exist? Easy file uploads aren't there? Built in persistence without having to fiddle with bouncers isn't there? Mobile apps that work well aren't there?
Whenever I'd had to use irc I have a horrible flashback. I used to have to install really shitty software. Now I can use a browser. Not that this is perfect, but it's one less hassle. Then I have to find the server which is running the channel and remember/google how the fuck you're supposed to connect to it. Then you have to type #join, and then..no, do you pick a nickname first and then join? You have to hope no-ones impersonating you because it seems there's no security model for irc at all - you just have to trust people. You try and talk but no-one replies. Is that because there's no-one there? It looks like there's a lot of people there but they have odd characters in their names and some of the colours are different. Are those offline colours? Do the characters mean they're bots? No, someone tells you you're on silent and have to type something before you can speak. Ok, i'm logging in because i asked a question earlier and now i'm using a different pc. I'll just scroll up....what the fuck? I can't scroll up? I have to just stay logged in like...all the time? Ah, you say - yes, but you can install some software.
Yes, that's where slack comes in. Except, instead of "install some software" you just "create an account" and log in and. Oh, that's it. Create a room, invite friends, or whatever. Post, DM people, scroll back, add rss feeds etc. It all just works. Nice android app too.
Not that i'm trying to sell slack; i can take it or leave it. I'm sure there are alternatives to that. But I have literally no idea why in 2016 anyone would want to subject themselves to irc (plus whatever other crap you have to install/configure to make it bearable).
I'll list some things I do in slack that I don't in IRC. Many of these are probably possible in IRC, but the fact that I don't do this in IRC suggests that there is more friction than slack.
1. Send messages to people that are offline.
2. Easily see unread messages in a channel.
3. Markdown formatting.
4. @everyone/@channel notifications (not to be abused).
5. Simple Github integration (and other apps).
6. Mobile notifications (in fact, just the overall state of "mobile")
I'm sure every single one of these could be added to irc via bot or something like that. The beauty of slack is that I can set up a slack team and do all of the above without having to really muck around with that. Much lower operational overhead.
Slack is to group chat like Dropbox is to file sharing.
There are plenty of old school ways to share/synchronise files among a group of people. You could run an FTP server and a bunch of automated scripts etc. Or you can just install Dropbox for your non-technically minded users and it just works. The interface is nice and mobile app support is great. Slack is similar in that regard.
It is substantially different. Getting all the additional stuff that Slack offers bolted onto IRC would be a pain. Not to mention trying to support end users.