Here Are Three Hot Apps You May Never Have Heard Of by Barb Darrow @FortuneMagazine January 19, 2017, 4:15 PM EST E-mail Tweet Facebook Linkedin Share icons Most people who work in or around the tech sector know about Slack, the hot chat app used by businesses of all sizes. But what about Zoom? Or Umbrella? or Teledoc? Use of all three of those products is on a tear among business users, according to a new survey by cloud identity management company Okta, which tracks app usage among its thousands of business customers. “What’s really interesting is what companies pop up,” Okta chief executive Todd McKinnon told Fortune. “Slack is not surprising now, but two years ago it was, and it skyrocketed in our data in 2015. Fast forward to now and here’s a set of companies, Zoom and a couple others that none of us had heard of not long ago.” To be fair, Zoom just raised $100 million from Sequoia and other backers, and so has gotten some buzz of late. But it is definitely on its way up, according to the survey. San Francisco-based Okta provides cloud-based tools that enable users to sign into many applications with one log-on and password and as such it gets a good view into what software its customers are using. Cisco csco Umbrella, was the second fastest growing business app overall in the survey. It provides security for a wide range of devices and comes out of Cisco’s acquisition of OpenDNS two years ago. Teledoc, a “telemedicine” company that enables virtual visits with doctors, was the fastest growing personal app in Okta’s universe. A personal app is one that you might use at work—to check you credit card statement, or book a reservation—but is technically not blessed (or paid for) by the corporate overlords. Other apps in that category that showed up in the survey come from State Farm Insurance, American Express axp , and Eventbrite, the online invitation and event service.. The reason Okta can track the use of these personal apps is that customers use Okta’s service to manage their identities across all business and non-business applications/ The most used app overall was Microsoft Office 365, followed by Salesforce.com; Box box ; Amazon amzn Web Services; G Suite; Concur, now part of SAP, and Atlassian team JIRA. Microsoft Office 365 and Google G Suite compete in the word processing, email, spreadsheet productivity categories. Salesforce is used by sales and marketing people to do their jobs. Box is cloud-based storage and file synchronization software; AWS is a slew of developer focused services; and JIRA tracks software development projects. That’s a diverse list which indicates that Okta reaches across a full spectrum of work groups within an organization. Get Data Sheet, Fortune’s technology newsletter. What’s interesting to a long-time tech watcher is whether smaller, innovative apps like some of those those mentioned can continue to hold their own against software behemoths like Microsoft msft , Google googl and SAP sap over time. It’s unclear whether a small company can prosper going forward given that once the big guys see a startup making progress in a given arena, they tend to jump into that arena themselves. Witness the November launch of Microsoft Teams to take on Slack. It’s too early to tell how that particular race is going although Spiceworks, another company that polls businesses about their tech habits, predicts Microsoft’s Microsoft Teams will surpass both Slack and Google Hangouts in usage by the end of next year. For more on Microsoft vs. Slack, watch: But Box chief executive Aaron Levie told Fortune that the modern era of cloud computing, which enables businesses to mix-and-match offerings from many vendors relatively easily, bodes well for the smaller companies as long as they keep innovating. This is Okta’s third survey in three years. While it did not specify sample size, two years ago it gathered data from 2,500 customers across 4,000 apps—factoring in millions of user logins. Those numbers have grown since then, but Okta would not specify them.