Google maps 'tens of thousands' of UK stores to work out whether ads attract customers to retailers

Google says it has mapped "tens of thousands of stores" in the UK in an effort to link its online ads to driving in-store purchases.

Google first announced its "Store Visits" product within AdWords — its search advertising platform — in late 2014. It rolled out to the UK in the summer of last year.

The analytics tool determines whether a person who clicked on an ad went on to visit a store, using data from Google Maps users on Android and Apple devices who have their location history switched on.

The user's unique Google ID links the visit with an ad that has previously been served or clicked.

Google aggregates and anonymises the data so advertisers don't know that a specific customer visited a particular location, but they can extrapolate whether their search advertising is lifting in-store sales in a meaningful way.

"Mapping" stores involves ensuring each retailer's Google Maps location is highly accurate, so it can pinpoint when a user actually entered the store (rather than stopping outside for a moment or visiting the store next-door.)