First-order effects

• Users who juggle personal and work accounts get native multi-identity login inside one Firefox window, removing the need for separate browser profiles or incognito workarounds.
• Sites and their embedded trackers see each container as a distinct identity, so cookies set in one context stop following the user into another.

Second-order effects

• Tracking-dependent ad platforms lose a cookie-correlation vector in Firefox specifically, pressuring them to lean harder on logged-in identity graphs — which is exactly what the later Facebook Container extension targets at its largest practitioner.
• Rival browsers face user demand for built-in identity separation, turning per-context isolation from a power-user extension into table-stakes privacy plumbing.

Third-order effects

• If the pattern holds, the browser itself becomes the enforcement point for privacy — culminating in Mozilla's later Total Cookie Protection, which partitions cookies by site by default rather than leaving isolation to individual extensions.
• Identity segregation shifts from a user-managed behavior to a browser-enforced default, restructuring how advertisers and platforms can build cross-site profiles at all.