There's plenty of room for competition, said Vanessa Thompson, a research vice president with IDC.
Slack's good timing and PR helped it capture the "eyes and ears" of venture capitalists, but the company also showed there are new options for solving the "increasingly systemic business challenge" of connecting project-based workers, Thompson said.
Modes of collaboration are converging from workspaces, presence, messaging, groups, activity streams, voice and video, she said. "New products can have any number of these capabilities natively or be able to connect with other services to serve broader needs," Thompson added.
Frequently, companies will use more than one collaboration tool.
"There is some displacement taking place, but we will see organizations running a number of Slack-type applications in parallel to solve different and diverse requirements," Thompson said.
Whether Slack's dominance continues remains to be seen.
"There's always the risk that the mega vendors in this space -- Microsoft, Google and IBM -- will decide they want to create something like Slack and bundle it into their popular collaboration and productivity portfolios," said Forrester's Keitt.
To keep growing its business, Slack will have to evolve its platform, and that poses risks of its own, he added.
While the competitive landscape may shift as more competitors emerge, there's no doubt of the category's continuing importance.
"The message is the atomic unit of collaboration," Preset said. "Organizations focused on communication really want to get the messaging platform right."
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