Mozilla has a strong policy on privacy and it's in a good position to wield some influence. Not as much as it would like, mind you, since most of what you can do online is governed and sometimes at the mercy of the sites you visit. In fact, you don't even have to visit a site to be tracked by it these days.
The Do Not Track initiative makes some headway, but it is entirely voluntary, it depends on advertisers actually respecting user wishes, with no way of enforcing them.
And even this weak policy is at threat of being dissolved as conflict between the parties involved, stirred by Microsoft's decision to not follow the Do Not Track standard, as proposed by the W3C.
In this environment, Mozilla is thinking at ways it could do better, work more to protect user privacy, while at the same time not "breaking" the Internet.
Mozilla doesn't as much as want websites to not be able to track users, but to have users in control of their data. The idea is for people to be involved, about what is being tracked, by whom and why, and be in control, i.e. be able to limit tracking to what they're comfortable with.
Sites do offer some privacy controls, but their effect is minimal at best. The obvious answer is to enforce privacy settings and options from the browser.
This seems to be a direction Mozilla is exploring. It's hardly alone, Microsoft has been building some privacy features into Internet Explorer for a while now. It could be said that IE has the most comprehensive privacy features.
The problem is with control, few people know the options are there and there's little control over them, you either enable them or you don't. Microsoft is taking the "daddy knows best" approach.
Mozilla wants to inform users first and foremost and then make it possible for them to make decisions and act on that information.
This is the idea behind about:trackers, an experimental add-on from Mozilla Labs which emulates how an add-on designed to limit access to user data would work. In this concept, websites would only be able to access data, such as cookies, on the terms defined by the user.
For example, sites would only be able to access their cookies on their own domains, not when a user is visiting other websites. Or a site would be allowed access to data for only one session.