Gmail 2-step verification.

Pro's: Increased security. 

Con's: Loads of set up routines per app. Can lock yourself out of account if not careful.

Only web-based apps on iOS supports the authenticator app. Other apps need application specific passwords.

Safety net:  10 backup codes/one login per code. SMS to phone. Better not use same phone as authenticator app ;)


Authenticator app starts without password/restriction and gives you ~30 seconds to use the one time password/number displayed.  Only works in web-browsers/html5 supported apps, making application specific password an must for most apps on the phone.


Authenticator app is possible to set up on two phones simultaneously, but needs access to both phones during installation. SMS service is sometimes slow, and not recommended for daily use.

Web browsers can be set to accept cookies, and grant permission per 30 day interval, with authenticator app, and 1st login password only.

Great feature, considering the increased risk of hijackings of gmail accounts lately. Suspicious activity or log in's from different IP's around the world shows up as warnings.