Citizen Lab, a research group, said on 12 November that Bloomberg has found more buyers of Webloc, a surveillance system from Penlink that runs on advertising data. Bloomberg's inquiry added agencies in the UK, the Netherlands, Germany, Mexico, Singapore, Saudi Arabia, the UAE and Israel. Citizen Lab's April report had listed potential customers in the US, El Salvador and Hungary. Since then, Austria's Ministry of the Interior has been confirmed as a customer too.
Citizen Lab built its April report from open-source research, freedom of information requests and a map of server infrastructure. The sources do not say which agency in each country uses Webloc, or what data it draws on. Citizen Lab calls the lawfulness of such systems in Europe and the UK highly controversial. Its researcher Wolfie Christl said the tool is moving down from military and intelligence bodies to federal law enforcement, then to state and local police.
General background, not a Webloc finding: apps and ad networks often record a phone's advertising ID alongside its location. Anyone who buys that data can follow a device over time. Teams that run ad code or sell ad data may want to check where that data ends up. That is this brief's framing, not a finding of the sources.