Everyone is talking about how Microsoft Office 365 is suddenly beating Google Apps

Microsoft has been telling us for eons that it is eating Google Apps' lunch, but hasn't backed that up with cold, hard figures.

Now, all of a sudden, sources all over the tech industry are noticing that Office 365 is everywhere.

And it's all because of one thing: Microsoft is telling customers to move their email to Microsoft's cloud instead of buying another Exchange server and hosting email in their own data centers, says Todd McKinnon, co-founder and CEO of Okta.

Office 365 usage has 'skyrocketed'

Take Okta, for example. Okta offers a security service that helps companies keep track of employee passwords and accounts to all the cloud services the enterprise uses.

It has over 2,000 customers tracking 4 million users, cofounder and CEO Todd McKinnon tells us.

"Over the last six to nine months, Office 365 usage has skyrocketed," he told us. "We see it on our network. We see usage of applications."

Up until last October, Google Apps was more popular, he said, and Salesforce and Box were the most popular apps used at work.

That's all changed. "Office 365 hasn't quite taken over Salesforce.com yet, but it probably will in the next few months," he says.

This is happening because Microsoft "is going around to every organization in the world and saying, 'hey, you know your email, you're on-premise Exchange server? You need to move that to the cloud. And here's financial incentives to do that." (Here's some details on how Microsoft is structuring those financial incentives.)

"It's like a tidal wave," McKinnon says. "Every company is looking to solve identity and mobility challenges because Microsoft is telling them to move email to the cloud."

Others see Office 365 everywhere, too

Okta is not alone in telling us this. Security service BetterCloud, which was 100% focused on security tools for Google Apps, just launched an Office 365 beta two weeks ago because it was getting so many inquiries from companies asking it for Office 365, a spokesperson told Business Insider.

Ditto for BitGlass, which also offers security services for Google Apps, Office 365 and Salesforce. In a survey of 81,000 users conducted a year ago, it found that Google Apps was far more popular, accounting for 16% of user's email, compared to Office 365 at not quite 8%.

In a survey it plans to release next week, the company revealed to Business Insider that Office 365 has now overtaken Google Apps in terms of usage.

"Office 365 has surged ahead of Google in the enterprise and is dominating future enterprise deployment plans (29%) versus Google Apps (13%)," a spokesperson told us.

To be sure, Office 365 is not taking market share away from Google Apps, but from old-school email software, mostly Microsoft Exchange.

Whereas about one-quarter of users Bitglass surveyed last year had email in the cloud, 42% of them are using cloud email this year.

Why is Microsoft winning? Workers like the Outlook email program, and they get that same Outlook look and feel with Office 365, McKinnon says.