By default, cloudHQ uses the OpenID Connect protocol to authenticate end-users. This means that cloudHQ does not store your password (or even hashed password). Your password is never send to cloudHQ servers. All authentication (verifying password, etc.) is done by Microsoft or Google.
Technically, OpenID Connect is an identity layer on top of the OAuth 2.0 protocol. It allows cloudHQ to verify the identity of the end-user based on the authentication performed by Microsoft Office 365, Microsoft Live Google, or Amazon.
The following identity prodivers are supported:
- Microsoft Office 365
- Microsoft Live
- Amazon
So, if your email is managed with Google, then you will be automatically logged-into cloudHQ as long as you are logged in into Google Gmail.
See http://openid.net/connect/faq/ for a set of answers to Frequently Asked Questions about OpenID Connect.