Report: Slack, Zoom growing among Office 365 customers

Most business licenses for the cloud-based productivity suite Office 365 include Microsoft Teams, but that isn't stopping some organizations from paying extra to use the competing apps Slack and Zoom, according to a new report.

Okta, a cloud security vendor, regularly tracks the apps used by its more than 6,500 customers, a cohort that includes many of the world's largest enterprises. More than 100 million people were using Okta's software as of January, giving the vendor insight into the business apps they use. 

Team messaging app Slack and video conferencing service Zoom are among the fastest-growing cloud products inside organizations using Office 365, according to Okta's data. The apps' growth comes despite Microsoft Teams offering the same core features at no additional cost.

The percentage of Okta's Office 365-subscribed customers using Slack increased from 28.1% to 31.2% between October 2018 and June 2019. Among the same group, Zoom use rose from 23.7% to 29.6% during the period.

Two years ago, 19.3% of Okta's Office 365 customers were using Slack, and 15.3% were using Zoom. 

Businesses that use cloud software from several vendors are more likely to be customers of Okta, which sells single sign-on software and other products that let companies set security policies across multiple apps. That means the specific percentages presented in the report may not be representative of the Office 365 population as a whole.

Still, Okta's findings demonstrate that businesses in growing numbers are using Slack and Zoom with Office 365 accounts. The report confirms a trend identified by analysts, who said that companies seem increasingly willing to support apps with overlapping capabilities if users take to them.

A recent survey of more than 600 businesses by Nemertes Research, for example, found that 42% of organizations using team collaboration apps like Slack and Microsoft Teams were supporting at least two of those types of products. And the majority of those businesses said they planned to keep it that way.

Slack and Zoom are "the only two apps out there that I've seen people form emotional bonds with," said Irwin Lazar, analyst at Nemertes Research. Both apps often gain footholds in large organizations through viral adoption of their free versions by small teams.

Slack and Zoom inked a deal earlier this year to more tightly integrate their products. Both also recently went public in high-profile listings that left each with multibillion-dollar valuations.

But they face an uphill battle against incumbents Microsoft and Cisco, which already have huge footprints in the enterprise market. Microsoft's Office 365 has 180 million monthly active users; Cisco's Webex video conference service has 130 million.

The companies also compete with Google, which offers messaging and meetings apps within G Suite.