Google has begun using billions of credit-card transaction records
to prove that its online ads are prompting people to make
purchases — even when they happen offline in brick-and-mortar
stores, the company said Tuesday.
The advance allows Google to determine how many sales have been
generated by digital ad campaigns, a goal that industry insiders
have long described as “the holy grail” of online advertising. But
the announcement also renewed long-standing privacy complaints
about how the company uses personal information.