If I understand correctly, for over a year Facebook would track users to web services that had Facebook integrations installed. It's not super clear what was different for "consensual tracking", but I presume this coincided with their privacy center?
> “Facebook’s user profiles would allegedly reveal an individual’s likes, dislikes, interests and habits over a significant amount of time, without affording users a meaningful opportunity to control or prevent the unauthorized exploration of their private lives,”
The Wiretap act seems like a bad precedent here. The problem isn't that that data was unwillingly intercepted (otherwise even things as simple as server logs would count as a wiretap), it's that people object to the way their information is being collected and aggregated. And there's no good law to really apply here without making a new one.