Someone needs to make a Persona Persona. We're our own worst SEO enemy :)
The Firefox themes were renamed to... background themes. It's just that the addons team (which owns getpersonas.org) has been hard at work on the new Mozilla Marketplace, and the Persona team has been hard at work on Persona. A few of the Persona devs are going to hack on this next month and try to get a disambiguation page deployed. We don't want theme-seekers to get lost, but we also don't want to lose people looking for the authentication system, so a straight 301 isn't ideal.
This link posted says they are looking to rename Personas to something different, but it doesn't look like its actually happened yet (or what it will be called). Given that the getpersonas.com website is still calling them Personas, I'd say the Personas name is still alive and well (and easily confused with the new Persona product)
Speaking of themes, how easy is it to customize the look&feel of the login prompt? It may be odd for the user to see an entirely different site when they try to sign-in to a site.
[1] http://www.getpersonas.com/en-US/
Evidently I need to pay more attention.