In their SEC filing for their IPO, Slack defined an “enterprise customer” as generating >$100k in Annually recurring revenue, which accounted for 40% of their revenue in the current fiscal year.  So, I was curious who their biggest customers really are.

Using click stream data from millions of users, Nacho Analytics mirrored Slack's analytics view for me. I was able to see a slice of their actual traffic to better understand what was really happening on their site.

It turns out they do have some pretty big enterprise customers: IBM, Oracle, Lyft, SAP, and VMWare are the top 5.  You might notice that those are all software companies, and that skew continues as you go down the list.  

Slack’s hardcore, early adopter customers were software developers. There are a ton of integrations with software development tools.  Atlassian - the company that makes some of the most used development tools - even shutdown their competing product in exchange for a stake in the company.

As the founder of a couple software companies and a sometimes slinger-of-code, I’m pretty up to speed on that stuff.  But, I was surprised at how significantly their customer base skews towards software-heavy companies.

Even when you look at customers that don’t specifically use the “” (the vast majority of customers) - they are still very software-centric.  The biggest ones tend to be global educational institutions or open source software initiatives.  Andela Learning Community is a Google-sponsored technical-education-for-Africa initiative. It holds three of the top 10 spots. VanHack is a “hackathon without borders”.  SkyEng is an English school for Russians.

Is this a bad thing?

I think that depends on your perspective.  There’s no doubt that Slack has a devoted user base of software peeps.  The question is, are they on the precipice of breaking through to a broader market - potentially changing the way all businesses communicate?  Or is it destined to be just another tool for nerds?

Honestly, I think you can find data in Slack’s customer list to support either side of that argument.  I’ll give you my opinion, but first let me address a little anecdotal confirmation bias: If I eliminate all the software people I have personally witnessed using Slack - so, my marketing team and (oddly enough) my 70-year-old parents - all of them prefer to use Slack instead of email.  I don’t know *anybody* that has used Slack that doesn’t feel like they have a productivity advantage vs email.  I’m not a Slack fan boy, but I do come into this analysis thinking that Slack-like communication will eventually replace much of what email currently does.  

When you get outside the top 5, and page through the top 30, enterprise customers in more traditional industries start to show up.  Walmart, Nike, Capital One, McKinsey, T-mobile, Comcast, NewsCorp are all customers.  Noting those last two, Slack’s second core audience might be media companies: NYTimes, NBCUniversal, Buzzfeed, Turner, and Nasdaq are also customers.    

Where Slack’s customers come from

Most of Slack's new team sign-ups come Directly - meaning they type "" into their browser.  The second most get there by a Google search, and 72% of the time they search for "slack".

That means that nearly 75% of Slack's new accounts are already familiar with their brand before they sign up.  Slack’s barely pays for *any* sign-ups.

So, if you think - like I do - that Slack-like communication is going to take over the mainstream enterprise and SMB market alike, then Slack’s market-leading position and ridiculous brand equity give them a potentially insurmountable advantage to take the lion’s share.