Ad-tech setting 'Privacy-Preserving Attribution' is opt-out in Firefox 128

Original Article ↗ Hacker News Discussion ↗

Firefox 128 quietly enabled a “privacy-preserving attribution” feature for advertising by default, prompting backlash from users who see any built‑in ad-tech—especially opt‑out and hard to discover settings—as a betrayal of Mozilla’s privacy branding and user trust. Supporters argue the system only shares aggregate, anonymized data and could replace more invasive tracking, while critics counter that it still expands the ad ecosystem, offers no direct benefit to users, and risks normalizing surveillance. The debate broadens into whether the web should rely on advertising at all, Mozilla’s growing financial ties to ad-tech, and interest in Firefox forks or alternative browsers that strip such features.

Opt-out vs. opt-in and telemetry

  • Some argue meaningful experiments/features can’t rely on opt-in because hardly anyone enables them; same view applied to debugging telemetry.
  • Others counter that many opt-in features succeed (e.g., extensions, cited opt-in telemetry projects), so “no one would opt in” suggests the feature isn’t user-beneficial.
  • Several commenters say the onus is on developers to make data collection obviously valuable to users (reliability scores, crash feedback), not just to the business.

Implementation and UX concerns

  • The “Privacy-Preserving Attribution” (PPA) setting is enabled by default in Firefox 128.
  • Commenters report the toggle is hard to discover: search for “advertising” in settings finds nothing, while the option exists under “Website Advertising Preferences.”
  • Some worry Mozilla will quietly re-enable such features on updates, citing past behavior with Pocket.
  • At least Firefox for Android Beta is affected (via about:flags); applicability to stable Android builds is unclear.

Privacy, security, and legality

  • Supporters describe PPA as aggregate-only measurement, using multi-party computation (DAP/Prio) jointly run by Mozilla and ISRG; no participant supposedly sees individual user data, and privacy only fails if both collude.
  • Skeptics argue:
    • Any additional data flow to ad tech is an “attack surface” for deanonymization, legal compulsion, or breaches.
    • Aggregate data is still valuable surveillance; users gain no direct benefit.
    • This won’t stop legacy tracking unless those mechanisms are actively blocked.
  • Disagreement on GDPR:
    • One view: no personal data means GDPR doesn’t apply.
    • Another: GDPR covers “any data collection,” so silently enabling this is at least unethical and possibly illegal. Outcome is unclear.

Mozilla’s incentives and reputation

  • Many see this as part of Mozilla’s shift into advertising: heavy dependence on Google search money, acquisition of an ad-tech firm, and collaboration with Meta-linked actors.
  • Some frame Mozilla as “controlled opposition” that ultimately aligns with big ad platforms.
  • The quiet, euphemistic rollout (“privacy-preserving,” minimal announcement) is widely seen as trust-eroding.

Views on advertising and funding the web

  • Multiple “reasons to hate ads” appear:
    • A: tracking and privacy invasion.
    • B: manipulation and attention capture.
    • C: resource theft (CPU, bandwidth), and a major malware vector.
    • D: encouraging unnecessary consumption and environmental impact.
  • Pro-advertising arguments:
    • Ads fund a large part of today’s commercial web; users overwhelmingly pick “free with ads,” and many jobs depend on this model.
    • A privacy-preserving attribution layer might make it politically and economically feasible to kill third-party cookies.
  • Anti-ad respondents reply:
    • Much of the web is unpaid user content; ads mainly enrich intermediaries.
    • The early, largely non-monetized web disproves the claim that the web “needs” ads.
    • Ad blockers are considered the correct response; many refuse any compromise and see ads-as-such as the core problem.

Alternatives and future browsers

  • Several recommend Firefox forks (Librewolf, Waterfox) or Tor Browser, which aim to strip out Mozilla’s ad/telemetry features.
  • Some look forward to new non-Chromium, non-Gecko engines (Ladybird, Servo) but acknowledge they are early, Linux/Unix-focused, and far from feature/performance parity.
  • Others prefer hardened Chrome/Chromium forks, or alternative engines like WebKit-based browsers, as pragmatic near-term options.