The online world is slowly moving from having a million accounts on sites everywhere with as much passwords to more unified logins which you can use on multiple sites. OpenID and Facebook Connect are two of those. But now there is Persona from Mozilla too.
Especially a system like Facebook Connect is worrysome since it needs a Facebook account and usually give out a lot of details you might not want to share with every site. Worse even, sometimes it’s the only way to login (like at the online music service Spotify).
This will put all your private info like your friends, where you go online, what games you play, what music you listen etc in the hands of one single company. And this company allowes itself to sell this data in any way they want.
Mozilla Persona is designed ‘with open-source non-profitness‘ to ensure more privacy.