Yes, this. But how the average user would respond to it and maybe a better question, on which type of websites that would make total sense?

I mean, would persona fit the e-commerce business just fine?

I run an e-commerce business and it works great. Persona really fits in well for all websites and when it is eventually integrated directly into the browsers, it'll be even more of a non-issue.

The more sites that adopt Persona, the more that the UX design and differences between sites will become a non-issue and posts like this where the designers are inventing yet another way of doing things will stop. Persona provides a clean standard interface that everyone knows how to use and even better... a single login.