For those of us who don't already know, this is U2F: https://www.yubico.com/about/background/fido/

Why U2F is betthern than using an Authenticator?

Here's a brief comparison between OTP (Authenticator) and U2F: https://www.yubico.com/2016/02/otp-vs-u2f-strong-to-stronger...

One big advantage of U2P is protection against phishing and mitm attacks, which OTP is vulnerable to. There is more information here: https://developers.yubico.com/U2F/Protocol_details/Overview....

U2F is immune against phishing.

Dropbox does too! Unfortunately, those are the only sites supporting U2F I know of at the moment.

http://www.dongleauth.info/ maintains a list of sites supporting U2F devices. There aren't many yet, but it looks like a Wordpress plugin exists that may end up in core. There are also a handful of additional sites listed in issues and pull requests on the site's GitHub page (https://github.com/Nitrokey/dongleauth).

(I'm not affiliated with the site, I just check it periodically and thought it might be of use here.)

Bitbucket as well.

That's new! Took more tries than normal to register, but that's great. They took so long to roll out even TOTP based auth, I figured it would be ages before seeing U2F.

Google also supports U2F

I wish AWS would!

GitLab supports it as of a few days ago :)

So what happens if you lose the dongle?

I have YubiKey Nanos "permanently installed" in each computer I use, as well as a portable one. If I lose all my computers, and my keys, and my phone... I guess I'll have to make a new Github account. It's all open-source anyway!

You can add multiple keys, so you could have a primary one that's with you and another one that's stored somewhere safe. You can also configure OTP and/or SMS-based 2FA and backup/recovery codes as a fallback mechanism.

You use the customer support backdoor.