FORTUNE -- Stewart Butterfield hasn't had a hit since Flickr, the photo-sharing site he sold to Yahoo (yhoo) back in 2005. But with Slack, his newish company's latest offering, the serial entrepreneur thinks he's on to something big -- a potential replacement to clunky, cumbersome e-mail systems.
"When I first started making software everything was Microsoft (msft)," says Butterfield. "Now every company has its choice [of software services] and as a result people's information gets scattered. E-mail no longer works -- it gives everyone a fragmented view of what's going on."
Slack's not the first product to try and replace e-mail, and it likely won't be the last. The software tool, which aggregates and organizes real-time messages, shared documents, and other communications between employees, was first announced last August and is now making its official debut. It integrates with existing web-based enterprise applications like Google (goog) Drive, Twitter (twtr), DropBox, GitHub, and task management service Asana. And it allows users -- typically smallish teams of five to 75 people -- to keep tabs on all messages in one place, get automatic alerts when their name is mentioned on any conversation threads, and, most importantly, easily search across disparate communication tools.
It sounds simple enough, but so far no tool has managed to effectively replace e-mail, despite repeated efforts and despite the fact that traditional e-mail has become such an inefficient time suck. According to a recent report from McKinsey Global Institute, the average professional spends about 28% of their workweek managing e-mail and nearly 20% of their time searching for internal information. And yet, "social" enterprise tools like Yammer (now part of Microsoft) and Salesforce.com's (crm) Chatter have been mostly additive in workplaces, forcing employees to adjust to another form of communication in addition to keeping their inboxes full of inbound mail. Other tools, like Asana and GitHub (both of which can integrate with Slack's service), serve their purpose, but also don't do much to eradicate e-mail from mainstream workplaces.
"E-mail will never go away, but it's become this massive dumping ground," says Gordon Ritter, general partner at venture capital firm Emergence Capital and an investor in enterprise software companies like Salesforce, Yammer, Veeva Systems (VEEV), and group messaging service Cotap.
But Butterfield says Slack's almost completely replaced e-mail between him and his employees. His company, Tiny Speck, originally started as an online game developer back in 2009, after raising $16 million from the likes of venture capital firm Andreessen Horowitz. Along the way, the team cobbled together its own internal collaboration system, built on top of a decades-old chat system called IRC. By 2012, Butterfield realized that his online game, Glitch, would never make it big. After looking at several other potential ideas (including starting his own bank), he settled on growing a business out of Slack, the then-rudimentary communication system he'd thrown together.
According to Butterfield, Slack's got 16,000 daily active users across over 1,500 teams. These employees used the service to send a collective 2.5 million messages last week, and early customers include Square, Urban Outfitters (urbn), and Harvard Law School. (Slack offers both free and paid versions; you can read more information on pricing here.)
Slack's got a nice, easy-on-the-eyes user interface and can weave in many of the tools companies are already using. But the best thing it has going for it is the ability to search and archive messages from the fragmented communication sources used by employees. Completely doing away with e-mail though is something that's highly unlikely to happen for years to come, particularly for any exchanges between different companies. (Slack and most of its competitors only serve communications between internal teams.) But Butterfield is convinced that some new, better tool -- whether it's Slack or something else -- will someday soon take over the painful, never-ending flooding of e-mail inboxes, CCing and BCCing, and back and forth e-mail chains and calendar invitations. And, though it's been a while, he has made the right bet before.