Cross-site tracking
The practice of following a user's activity across different websites, typically through third-party cookies, embedded trackers, or browser fingerprinting.
Cross-site tracking is how advertising and analytics companies follow one person across unrelated websites. The classic mechanism is the third-party cookie: a tracker embedded on many sites sets a cookie once and reads it everywhere, linking visits into a single behavioral history. Supporting techniques include tracking pixels, link decoration that carries identifiers between sites, and server-side identity graphs that join the pieces together into a profile used for ad targeting and measurement.
Browsers have moved against the cookie-based version of this: Safari and Firefox block third-party cookies by default and Chrome has been restricting them. The practical consequence is that tracking shifts toward browser fingerprinting, which needs no stored state and survives cookie clearing. That shift matters for privacy, because it moves identification from something users can delete to something computed from the device itself, and it is why fingerprint behavior has become central to the tracking debate.
Profile isolation is a structural answer: Oculr keeps browsing identities separated, with each profile holding its own cookies, storage, and fingerprint, so activity in one profile is compartmentalized from activity in another rather than accumulating into one cross-site history.
