Slack makes no secret of the fact that they set out to kill work email.
I get it. It's a noble cause. I don't know anyone who doesn't wish they had less email to deal with. In fact, the average worker spends 10-15 percent of her time just dealing with email. That's not work, that's something somewhere south of Dante's fifth circle of hell.
It's no surprise then, that so many organizations and businesses have been eager to try an alternative that promises to get back all of that time. And in some ways, Slack does that really well. For group conversations, in particular, it can be really useful.
Threads are actually a really helpful way to keep conversations organized so that you can see in context how important discussions unfold. Except no one actually uses threads. At least no one on any of the teams that I've worked with on Slack. Mostly, everyone just adds messages one after another on topic after topic.
Following any one conversation is kind of like swimming up Niagara Falls. And we don't even have time to talk about notifications. The little red dot on my Slack icon won't go away because someone is always posting something that apparently requires my attention.
Slack isn't good for everything.
Think about this way: Imagine for a minute that a family of beavers decided to call home the space immediately next to your desk. Then imagine that family of beavers decided that every few minutes, while you were in the middle of preparing the most important sales pitch of your career, they'd invite you to come to play games.
Never mind that you have work to do. And never mind that there are probably important conversations going on around you that most likely impact that work, you're never going to know about any of it because that family of beavers is making so much noise that you decide to pack up and go work at Starbucks instead.
That's basically Slack.
Email is better for many work conversations.
Slack isn't going to get rid of email, because honestly if I need to share an important file with someone, I'm going to email it. If I need to track when a message has been opened or read, I'm going to email it. If I have to send a message after-hours that I want to be sure actually gets looked at the next morning, I send an email.
Also--everyone has email. And everyone knows how to use email. My mom can use email (though getting her Outlook calendar to sync with her iPhone seems to be about as promising as escaping a collapsing black hole). Neither of those is true about Slack, especially the second.
Slack has its own strange lexicon that requires understanding things like "bots," and "giphy," and "channels." And you have to post things in the right channels, or else the right people might not see it, and the side effect is that you might derail that channel for the rest of the day. You also might get yelled at by the official "Dean of Appropriate Slack Usage" for your organization. If you use Slack you know I'm not even kidding.
And the beavers. They're in there too, sharing pictures and random GIFs and videos of their favorite Friends episode references.
Save Slack for casual conversations that can't occur in real life.
Here's what Slack is good at. It's good for remote teams who need something to create the feel of the casual interactions that naturally happen in a physical workplace. Slack is basically the virtual version of conversations that happen right outside your office door (channels), or the teammate that knocks on your door for a quick question (direct messages)--but for people who don't have an office door. Or work in an office for that matter.
Don't underestimate what a big deal that is. It's huge for distributed teams and remote workers and Slack's actually really good at it. Like, really good. I work from home and write for a living. Most of my co-workers are hundreds, or sometimes thousands of miles away, but this actually helps foster an authentic connection with people I've never met. It creates conversations and context that just don't happen in group video meetings or emails. It's actually the biggest benefit of Slack in my opinion.
Still, that's not a case for replacing email. It's actually something totally different. In some ways, it's probably just as important and noble a cause.