Work conversation tool Slack raises $43M

Another indication that we are on the cusp of a revolution in work technologies: Slack, the work conversation app from Tiny Speck, has raised a round of investment of $43 million at a $250 million valuation. The investors include The Social + Capital Partnership, Accel Partners and Andreessen Horowitz, and a few angels, like Gigaom’s founder Om Malik, Yelp CEO Jeremy Stoppelman, Squarespace’s Anthony Caselena, and Stripe’s John and Patrick Collison.
[Disclosure: Om Malik is the founder of Gigaom, and is a partner at True Ventures, which is an investor backing Gigaom.]
Slack only went live in February (see It’s getting even more real time: Slack and Skwiggle), and is the brainchild of Stewart Butterfield, the co-founder of Flickr. As I said at the time,

Slack is the conversational tool from Tiny Speck, founded by Stewart Butterfield of Flickr fame. He signed up 8,000 companies in the first 24 hours after the launch in August, and it is intended to be more than just a chat utility. It also serves as a file manager — based on its search, it’s much better than storing anything on your hard drive –and as a Yammerish work media tool. But his aspirations are greater: he wants Slack to be the social layer for a company’s information flow on tools like Dropbox, Zendesk, Heroku, and Helpscout, where the messages from those apps would surface in appropriate chats on Slack.

Slack is best compared to Atlassian’s Hipchat: they both have persistent chat histories, file sharing built in, and are strongly oriented toward the mobile experience. Accel is an investor in Atlassian, so they are really betting on work conversation tools.
My sense is that we are seeing the first signs of the next generation of work technology: context-framed conversational tools that break away from the mainstream, tired static ‘collaboration’ architecture based on top-down information sharing and archival, and instead support flexible and connection-oriented cooperative work based on bottom-up search.
We should see this sector heat up: Dropbox had been sniffing around Slack, but acquired competitor Zulip (see Dropbox acquires Zulip, readies two-headed client). We should see an closely integrated solution emerge there in short order. As I wrote that the time:

I am betting that they will build a Stream-like integration of that topic-based chat service right into Dropbox. (If you check out the Zulip features, you’ll see they have almost everything in hand.)

And they are keeping their cards very close to the vest, basically keeping what’s planned under the radar.