[petercooper]

I know next to nothing about AD, but my company appears to match against this merely because we have an Office 365 account (from which we do nothing except download Word and Excel every now and then) so it doesn't necessarily mean you're using whatever it is much.

[flumpcakes]

If you have Office 365 you have AAD. If you use pretty much any cloud hosted Microsoft business services, (E# licenses) you are using AAD. If you are using Azure, you are using AAD.

[rejectfinite]

You dont use it for email/exchange online?

All 365 accounts get created in AAD. And your user has access to the portal even. https://aad.portal.azure.com/