Why Slack Works.

On context switches. And user epiphanies.


There’s something about instant messaging that makes it inherently addicting. Probably the fact that it’s asynchronous, yet it can be real-time and synchronous when you need it to be. Or maybe it’s the tiny dopamine rushes that we get each time we see a notification or the little “double check” read receipt. And unlike email (which is also asynchronous), messaging is relatively frictionless — it brings with it none of the baggage or expectations of etiquette that make email such a chore.

Little wonder then (and I admit that I say this with the gift of hindsight) that the next wave of enterprise collaboration tools will be led by a slew of slick, beautifully-designed, real-time messaging applications.

The rather curiously named Slack.

But maybe I’ve got it completely backwards. Maybe the designers of IRC had it all figured out more than a decade ago.

HexChat, an IRC Client (circa 2014)

Then again, maybe you don’t have to reinvent a paradigm that works well. Maybe you just need to adapt it, and then build on top of it.

What Slack Gets Right.

When I first heard about Slack, I was skeptical. I wasn’t sure why we needed yet another chat platform for teams. I’d used Campfire and Grove.io in the past, and they didn’t quite end up sticking. But I decided to give Slack a try for a web development class that I took at MIT, and I believe I now understand why so many teams swear by it.

My hypothesis is: the reason that Slack and HipChat feel magical once your team begins to adopt them is because they really reduce the cognitive overhead of context switching between the different silos of information that we have to switch in and out of every day. Unfortunately, as is the case with most productivity tools, this is a problem that most of us don’t realize we have. In some ways, it’s a bit like the epiphany users have when they discover Dropbox for the very first time — once you’ve used it, you don’t know how you ever got by without it.

It’s all too easy to ruminate and preach about why successful products take off, when often the real reasons are ones we’ll probably never know. So I won’t pretend to claim that I understand how Slack built traction and launched itself into the incredible trajectory that it’s currently on.

What I will do though, is list what I believe Slack did (and does) really well:

1. Cross-device sync that REALLY works.

The first thing struck me about Slack was how well messages (and state) sync across devices. If I’ve read something on one device, my other devices know and take me exactly where I need to be. This becomes all the more important in a communication app because you never want a user’s train of thought to be interrupted. This is hard to achieve at scale, and it’s a pet peeve that plagues millions of users of iMessage and other messaging platforms every single day.

2. Fast, full-text search.

Over time, Slack ended up becoming a repository of information — messages and attachments — for our team, and it became extremely important to be able to search for anything. As a user, you begin to share important information in a channel, safe in the knowledge that you as well as your teammates will be able to retrieve it when it’s needed. This “shared intelligence” becomes extremely valuable for teams over time. This is a feature that really sets Slack apart from the HipChats, the FlowDocks and the Campfires of the world.

3. Integrations.

Slack does the basics really well, but integrations are another area where it really begins to shine. I wired it up to Github, Google Docs, and Asana, and that’s when I had my AHA! moment. It’s incredibly helpful to be notified whenever teammates complete important events (complete a task, add a document, or commit code) and to be able to walk through a linear history of all team activity — it leaves you feeling like you’re completely in sync with the rest of the group and on top of things. Integrations (with search) elevate Slack from being a simple chat room to a real knowledge archive.

4. The Little Details.

Stellar products are seldom just about usability and usefulness. They go a step further and strive to delight their users. Slack does this time and again, and it’s these little things that make it such a joy to use. We’re often quick to gloss over and dismiss these seemingly inconsequential details, but I’d argue that they warrant more credit. After all, it wasn’t search result quality alone that catapulted Google into the driver’s seat — it was (among other things), a million delightful details that endeared the search engine to its user base. I’m going to let Slack’s users (who have taken to Twitter to share their delight) back me up here:

What’s on the anvil?

Slack has witnessed hyper-growth over the past year, fueled by a well executed launch, and strong word of mouth. And the team has a compelling vision, articulated beautifully by founder Stewart Butterfield in what now is one of my favorite essays: “We don’t sell saddles here”.

Slack’s DAU growth (from the Slack blog)

The jury’s likely still out on whether Slack can live up to its heady valuation. What’s not in doubt though, is that Slack is a simple yet incredibly useful product — one that becomes the nerve-center of teams that start using it.