I'm more interested in their privacy policy:

"SHARING YOUR PERSONAL INFORMATION: We share your Personal Information with third parties (analytics tools) to help us use your Personal Information, as described above. We use analytics tools to track our users to improve our product and provide a better experience."

Calendars, like contact lists, like emails, like all of the other personal content people produce everyday is sensitive. In lieu of saying how this is protected, apart from just saying it's simply used to make things better, I'm reluctant to link any accounts containing sensitive personal data to startups in search of a revenue-generating business model.