We were born in the cloud and have chosen Cloud IdP rather than adding yet another entry to the list of accounts that needs to be managed and secured.
A Cloud IdP is not just a way to access services across what has become borderless global information sphere, it eliminates of a whole class of attacks you've probably read about in the papers and also serves as a risk transfer (away from us and you, toward a trusted third party).
Currently we support Google's OAuth IdP. We've got support for services in the Microsoft ecosystem roadmapped up next.
Both Google and Microsoft allow syncing of an internal directory (eg, Microsoft Active Directory). For companies who prefer to accept the risk of managing an identity directory without a moderating cloud service we also plan support of SAML identity federation.
Google's OAuth is available for any type of Google account (free or paid G Suite) and in our opinion is a pretty hard nut for attackers to crack.
In addition to the free GMail accounts you may be familiar with, Google also offers a no cost "Cloud Identity" service which allows organizations to centrally manage identity services (https://support.google.com/cloudidentity/answer/7319251).
Use Google Authentication anywhere you see "Login with Google" on the internet.