Against all odds, Slack has emerged as the darling of enterprise chat.

The competitive deck appearsnearly stacked against the startup, and it seems that every other month a new product launches from a major tech company thats billed in the tech press as the next Slack Killer.

What Slack does isnt actually all that original as startup ideas go. It merely provides an environment for teams to share information inside a chat client. Yet it has been able to ride a wave of popularity, attracting users, capital and a set of worthy challengers.

Even as Slack makes IPO-sounding noises, competitors continue to saddle-up. Perhaps, then, its the perfect moment to take a look at the enterprise chat space and what all of this activity means for Slack as it battles the giants of the tech world.

Slack by the numbers

Since Slack launched four years ago it has raised more than a half a billion dollars, pushing its valuation to $3.8 billion. Whats more, the company has gone from zero to 5 million daily active users in the same period.

Those results have generated remarkably quick revenue growth. The company surpassed the $100 million revenue run rate mark last year, despite what appeared to be extremely stable per-seat revenue. That matters as the company rolled out its enterprise product earlier this year. Slack claims it will work for up to 500,000 employees, which should put to rest the criticism that the earlier version of the product couldnt scale, and could help increase the yearly revenue generated by each user.

If Slack can keep attracting new seats and increase revenue per user, it may manage another few years of hyper growth. Yet, even as the new version becomes key to its future revenue mix, the company managed to grow while maintaining its pricing position.

Specifically, it was able to double its annual recurring revenue from $25 million in June of 2015 to $50 million by December of that year, then double it again growing to $75 million by April 2016 and more than $100 million by the end of last year.

That kind of performance attracts attention.

Stampeding incumbents

Slacks success has led to a lot of action in thisspace in a short time.Each Slack competitor has its own particular niche.

Microsoft Teams, which just announced full integration across Office 365, is, at its heart, the tool for folks fully invested in the Microsoft ecosystem. Facebook at Work wants to be the communications tool for the entire company, regardless of your role. Google just announced it was splitting Hangouts into Chat (yet another Slack Killah) and video and its going directly after Slacks collaborative approach in the chat part.

Atlassianoffers a wide range of collaboration tools that focus ondifferent roles, Salesforce Chatter concentrates on life inside the Salesforceplatform, Cisco Spark has broader unified communications ambitions, Yammer (which Microsoft purchased in 2012 for $1.2 billion) is an older attempt at the same idea and Convo is a startup with its own cloud-based chat service, which hasnt gained quite the same traction as these larger players.

Lets not forget that none of this is new, and there have been attempts to sell this kind of software in the enterprise in the past. It just seems only in the age of mobile, social and cloud has it finally found a meaningful foothold and begun transforming the way peoplecommunicate across the enterprise.

In platforms we trust

Modern tech giants are platform plays with tendrils extending across product categories. That means that Google and Microsoft and Amazon and Apple sell music, and Google and Amazon and Microsoft will keep experimenting in social until something sticks, and explains why Google and Microsoft both torched billions of dollars trying to break into mass-market smartphones (Facebook and Amazon have history there, as well), and on and on.

Slacks key differentiator is that it strives to be more than a simple chat service. It wants to be a platform in its own right, taking advantage of chatbots and plug-ins to be the center of your work life. This could allow Slack users to access information from many common enterprise applications such as Salesforce, Zendesk, SAP and others without leaving the chat client. This ability to connect to other enterprise applications in a simple way, giving users a long-sought single place to work without having to constantly switch focus, could be the secret to its success.

If Slack can plant the seed of a new productivity platform inside of a dizzyingly expanding set of customer companies small and large, its attacking incumbents twice: If it can supplant other large-scale tools at big firms, Slack undercuts enterprise-facing revenues currently collected, and if smaller companies pick Slack and its nascent platform overtraditional productivity stacks, it could further undermine future income streams from these large companies.

Against that backdrop, its no wonder that these large vendorssee Slacks capabilities as a threat and are attempting to undercut its influence by offering similar functionality, driven by the power of their brands.

But whether these incumbents can blunt the momentum Slack has built up in such a short time remains to be seen. While theres likelyroom for more than one winner in this space, Slack has shown its simple centralized workplace model could be a worthy adversary to some of the biggest names in the business.

Alex Wilhelm is the editor-in-chief of CrunchBase News.

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