Office 365 is a cloud-based version of Microsoft Office that includes business-class email, web conferencing, and file sharing. It includes no advertising, and all of your data is kept separate from consumer services. Your data belongs to you and you can remove it whenever you want to.
If your organization is considering moving productivity services to the cloud and has questions about protecting the safety of your data, we have answers about Office 365.
More information about privacy and security in Office 365