Jan 2, 2019 · 37m · a16z
a16z Podcast | Tools for How We Work Today
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gold bands on the timeline = statements, start to end. Hover to read, click to jump. CC turns on captions
In this episode of the a16z Podcast, Slack co-founder Stuart Butterfield joins host Steven Sinofsky and Benedict Evans to discuss the origin, product philosophy, and impact of Slack. The conversation covers how Slack evolved from internal game development tools into a centralized hub that replaces fragmented email and rigid enterprise software with flexible, searchable communication streams.
How this conversation actually went
Every chapter scored 0–10 on four independent dynamics. Hover any point for the reasoning behind the score. How this is scored →
The host as informed peer 5.6 Guest teaching 5.6 Guest disagreement 1.2 The host pushing back 1.2
speaking balance: gold is the host, purple is the guest (3 minute bins)
Sharpest disagreement ▶ 28:36 Rejection of the Email Killer Narrative
Stuart forcefully pushes back against media headlines framing Slack as an email killer, arguing that email will remain vital for decades across organizational boundaries.
Hardest push from the host ▶ 10:52 Host Defends Microsoft DominanceSinofsky interjectingly rejects Stuart's framing of Microsoft's 1990s market dominance, clarifying that customers actively chose Microsoft products rather than being passively dominated.
Biggest teaching moment ▶ 28:36 The All-or-Nothing Reality of Communication ToolsStuart educates the hosts on the binary dynamic of internal collaboration platforms, demonstrating why 80% team adoption leads to complete failure if trust in message delivery is lost.
The host holds their own ▶ 37:15 25 Years of Enterprise Software PerspectiveSinofsky leverages his 25+ years of software leadership to reframe Stuart's points, highlighting how traditional enterprise software always faltered by forcing rigid structure and cataloging first.
the scores for every segment, with the reasoning behind each
| Chapter | Topic | The host as informed peer | Guest teaching | Guest disagreement | The host pushing back | Why |
|---|---|---|---|---|---|---|
| Defining Slack as a Centralized Communication Hub | 4 | 5 | 1 | 1 | Sinofsky asks Stuart for a concise elevator pitch of Slack, prompting an explanation of its search, integration, and cross-platform architecture. Benedict Evans extends the discussion by analyzing how Slack acts as a universal interface replacing specialized app UIs. The tone is highly collaborative and exploratory. | |
| Fragmented Cloud Software and the Piler Versus Filer Shift | 7 | 5 | 2 | 3 | Sinofsky draws on his background leading Microsoft Office and Windows to debate 1990s tech dominance and discuss the transition from 'filers' to 'pilers' in information management. Stuart carefully hedges his critiques of legacy tools like Outlook while Sinofsky playfully acknowledges Outlook search limitations. | |
| Reducing Friction, Enterprise Adoption, and Mobile Dynamics | 6 | 6 | 1 | 1 | Sinofsky queries how enterprise IT org structures conflict with flat, un-filed cloud tools. Stuart details how micro-friction reduction like slash commands increases operational discipline, while sharing detailed telemetry on mobile versus desktop daily active usage. | |
| Organizational Transparency, Cultural Changes, and Team Growth | 5 | 6 | 1 | 1 | Stuart outlines how Slack creates transparency for new hires and cross-departmental awareness, while explaining why internal messaging tools require 100% team adoption to succeed. Benedict and Sinofsky offer complementary industry parallels around media workflows and SaaS reporting. | |
| Product Philosophy and Avoidance of Rigid Enterprise Ideology | 6 | 6 | 1 | 0 | Stuart breaks down Slack's core product philosophy of avoiding embedded enterprise ideology or rigid database schemas like traditional task managers. Sinofsky validates this insight using his quarter-century of experience in software development. |
Statements from this episode (14)
Butterfield: IRC only has a few hundred thousand global users left
“Only a few 100,000 people left in the world who use it.”
Butterfield: Early Slack team grew to 45 employees using zero email
“When we hired the first employees, the number five at the company through to the 45th employee, everyone got an IRC, everyone started using it, and we didn't use email at all”
Sinofsky: SharePoint originated as an internal repository for Office specs
“We were trying to build the specs for Office, and of course, we didn't quite know what to build, so we built like a spec place to put all the Word documents and spreadsheets, and that became SharePoint.”
Butterfield: Slack routes all company alerts, tweets, and tickets into Slack
“In our case, every time someone tweets at us at our company, that goes into our Slack instance. Every time a the customer creates a ticket through Zendesk, that goes into our Slack instance. Every time someone signs up for the service through our own internal …”
Butterfield: Centralizing tools in one hub outweighs better standalone UX
“Yeah, and I'd even be willing to admit that in many cases using a purpose-built specific tool for each of those items might be the better experience, but the value of having them all in one place just so completely overwhelms any benefit you can get by splitti…”
Butterfield: Search-centric tools drastically lower cognitive cost compared to manual filing
“Where it wasn't just the fact that you could search for the messages and find them again after, which obviously is very important, but the cognitive cost of processing incoming messages fell through the floor in comparison to a world where you had to manually …”
Butterfield: Slack intentionally excluded mobile-only jobs, omitting 70% of US workforce
“We explicitly said at the beginning, and this has still been our experience, that Slack is not really designed for a mobile-only workforce, and not designed for jobs where people aren't going to have a computing device in their hands most of the time. So we au…”
Butterfield: 99% of Slack DAUs use desktop, 65% mobile
“99% of our daily active users will log into Slack at least once on that day that they're active on the desktop, but only about 65% will do the same thing on mobile.”
Butterfield: Facebook at Work will fail to replace internal email
“This is, by the way, what I'm thinking is probably gonna happen with Facebook at work, too. It wasn't quite sufficient to replace email usage internally, or it wasn't quite sufficient to replace use of messaging internally, or whatever it is.”
Butterfield: Slack adoption is binary and requires 100% team usage
“And what we found is that success with Slack is very binary. If we get to 80% of the of the team using Slack, it might sound like I'm about to say something good, but no, zero percent will be using it soon. It has to be a hundred percent.”
Butterfield: Heavy email usage will continue for at least 30-40 years
“And I want to just stress, because we get this in headlines quite a bit, that we want to be an email killer. Not going away. We've got, you know, at least three or four decades left of heavy email uses because it is lowest common denominator, and I mean that i…”
Butterfield: Knowledge teams relying on internal email will lose to competitors
“But I think if you use email as your primary means of communication internally for the kinds of knowledge worker, for lack of a better term, teams that use Slack, that's, you're foolish. I mean, and it's such a big disadvantage that you will eventually be made…”
Butterfield: Slack intentionally omitted structured task management features
“When we were first starting on this and we thought about the core feature set and what we wanted to get in and what we didn't want to be, do we decided we wanted to avoid anything that has too much structure or too much ideology behind it, and so Task manageme…”
Butterfield: Hardcoding workflow ideology into database schemas limits software adoption
“The more specific you get, the more that ideology gets cooked into the model, or the scheme, I mean, in the literal sense, the database model, like the field names, and what columns you have the less likely it is going to work for any Given individual, because…”