At OpenRent [1], we use the google identity toolkit [2] and whilst it has a few quirks and bugs, it's been received fairly well by even our non-tech crowd. It u

At OpenRent [1], we use the google identity toolkit [2] and whilst it has a few quirks and bugs, it's been received fairly well by even our non-tech crowd. It uses email providers as identity providers - and is only as intrusive as inputting your email into a traditional log in box, just with much less friction, and without the requirement to remember another password! I'm surprised it's not seen bigger adoption in the start-up crowd, but I guess it was slightly more work and isn't quite in-line with the MVP culture. It also places a reliance on a third party - but in this case I expect good reliability from Google, and have a fallback option in place (both for availability, and to support older browsers). [1] - http://www.openrent.co.uk http://www.openrent.co.uk [2] - https://developers.google.com/identity-toolkit/ https://developers.google.com/identity-toolkit/