I'm sure Firefox will release a Firefox plugin that will complement the basic service of identification. Imagine a plugin that lists all the websites you can authenticate with Persona. Or what if you had multiple personas, the firefox plugin can help you manage the selection of personas. Eventually, it'd become baked into Firefox, giving users that sense of it fundamentally "safer" than other browsers. Sure, this is all speculation, but it's a good marketing strategy on Mozilla's end and the start of gaining back the average consumer market share.