An email replacement may finally have arrived: Slack.
We started using Slack for internal communication in April 2014. I pulled the past 11 months of my computer activity from RescueTime to see how my use of email vs. Slack has changed.
Normalizing time spent on communication is hard. External communication changes seasonally, as fewer people want to talk to investors in August or December, and over the past year my absolute volume of email has grown.
However, it is clear that Slack’s share of my total time spent on work related communication has significantly increased as we have shifted more and more internal communication from email to Slack. In May, 4.6% of my time was in Slack, and in January it was 13.5%.
I think Slack is a better tool for internal communication. Aside from centralizing communication and digital assets to optimize collaboration, below are the three main reasons I think many teams would benefit from separating internal and external communication:
Cognitive Separation: Internal and external communication often have a materially different cognitive workload per email. Internal communication should have quick turn arounds, and flow freely. External communication should be polished and thorough. Teams shouldn’t handle quick 1-line responses to their team in the same email session as paragraph responses to 3rd parties.
Prioritization: If a team is distributed and busy yet trying to move quickly, it should still be easy for everyone to stay in-sync and have quick discussion cycles. When communication happens in email, it gets lost among external communication that can require much more thought to respond. There should be a separate place to make sure no team member is a block to any other person’s work. Related to prioritization, a team should be able to reach a colleague at any moment, but external demands may not be as immediate and could wait until the next morning etc.
Streaming vs. Threading: It is quicker to scan through a feed then scan through emails. A chat stream enables quick scrolling through a discussion. Email threading requires processing each message and has a lot of meta text that clutters the UI. This makes catching up much faster.