To use the feature, you (apparently, I haven’t used it yet) have to send Google a record of every website you visit. A cookie is then used to record your behaviour data when using Firefox, providing it to Google for their own purposes.
It’s an opt-in scheme, so it won’t happen without your permission, but then it could be buried in some terms and conditions that a user may not bother to read if they’re more concerned with protecting themselves from phishing attacks.
On the flip side of the coin, commentators say that Google probably aren’t doing anything with your data that your ISP and other online companies that you interact with don’t already do.
As the Platinax site notes: “The simple truth is that online privacy is already a mess, and that internet users are often simply not allowed to determine how their personal data may be collected, used, or processed.”
Mozilla are now a ‘for profit’ group, but have they sold out for the sake of profits?