We use google to host our Staff e-mail accounts, I've already implemented SSO in Knack.
What would be even more useful though is if the user accounts for our Knack database automatically synced with our Google user accounts, so that the administrator only has to worry about one user management screen when creating accounts for new starters or removing accounts for leavers.
We currently do this with out Staff Portal which is hosted by wordpress and it's fanatastic. Be great if you guys could implement it as well so that we can simply things even further.