Chances are if you’ve recently worked in an office or worked remotely, then you’ve been asked to use Slack. The workplace instant messaging service is designed to help teams collaborate, both locally and across geographical divides. Now the company behind it is about to go public.

Slack is not the only player in the workplace messaging space. It has competition from Microsoft, Google, and Cisco, but Slack seems to have caught the working public’s imagination more than any other platform.

A report released today by Mio, which helps companies integrate messaging platforms, says 74% of companies with over 10,000 employees report they are now using Slack. It’s particularly popular amongst startups. In its prospectus filing with the SEC, Slack reports it has more than 10 million daily active users.

Slack allows person-to-person chats and file transfers, as well as group conversations. If your company is anything like Marketplace, then the most popular channels are non work related. “The good lunch” and “now reading” channels see regular updates, and workplace experts say it’s that flexibility over what people, and teams, share which makes Slack useful.

“Ultimately, anything that gets people off drowning in email is a good thing,” said April Rinne, who advises startups and other companies on the digital economy and the future of work.

“When I look at Slack, what it does is two things. It allows you to control whether you opt in or out of conversations. And secondly, it does make it easy to plug in other things to its application.”

Developers can create databases, time management tools, or collections of GIFs, that can all be accessed from within Slack and quickly shared with co-workers and friends.

Not everybody feels that Slack gives them more control over messages though. For some, Slack notifications interrupt a creative flow, with their distinctive “knock brush” sound effect. And if you have the Slack app on your phone, it can be hard to delineate personal time, or vacation, when the messages reach you anyway.

Slack’s determined to keep growing and stay flexible. In its prospectus it says “we (and the rest of the world) still have a hard time explaining Slack. It’s been called an operating system for teams, a hub for collaboration, a connective tissue across the organization, and much else. Fundamentally, it is a new layer of the business technology stack in a category that is still being defined.”

Submit a form.