Why it feels like the ads are watching you
Apps can embed SDKs from ad networks and analytics companies. Those SDKs can report what you're doing to shared tracking infrastructure. When several apps on your phone report to the same networks, the ad you saw on one app can resurface on another.
Why a browser extension doesn't fix this
A browser-based tracker blocker only ever sees traffic that passes through that browser. The SDKs inside your other apps are completely invisible to it. That's why someone can run a careful ad blocker in Safari and still see a retargeted ad show up in a different app.
What network-level filtering blocks
Filtering at the network level — rather than inside any one app — blocks known tracker and data-broker domains before they can complete the request, regardless of which app sent it. Casper's Cloak applies this kind of network-level tracker blocking across every app on iPhone, Mac, and Android, targeting known tracking SDKs and data-broker endpoints, including trackers that disguise themselves to dodge browser-only blockers.
A reasonable expectation to set
This reduces your exposure to catalogued tracker domains — it isn't a claim that no tracking signal of any kind ever reaches an app again. New tracker domains appear regularly, and filtering lists get updated to keep up, not guaranteed to be instantaneous.
Casper's Cloak is one subscription covering iPhone, Mac, and Android — tracker blocking, phishing and malware filtering, and an encrypted VPN tunnel together. See current plans on the subscriptions page or read more about the tracking mechanics on the tracker-blocking page.