Oath, the Verizon-owned digital content unit that operates Yahoo has reportedly been offering advertisers the ability to target users based on the contents of their emails, a practice that has been commonplace in the past but has recently come under fire as breaching consumer privacy.

According to the Wall Street Journal, Oath has been pitching advertisers a service that analyses more than 200m Yahoo Mail inboxes and produces rich user data based on the contents. The data provides marketers with clues as to what users may be interested in buying, as well as being used to generate demographic or behavioural tags based on identified interests.

“Email is an expensive system,” said Doug Sharp, vice president of data, measurements and insights at Oath, in a statement to the Journal. “I think its reasonable and ethical to expect the value exchange, if youve got this mail service and there is advertising going on.”

The practice of scanning user emails is not a new one, but Yahoo appears to have expanded its own version of this service since it came under the umbrella of Oath in 2017, following its acquisition by Verizon. Oaths privacy policy also allows for Yahoo employees to review sections of some commercial emails.

Google ended its own use of email scanning for ad targeting last year, but recently drew criticism for failing to take action to protect inboxes from third-party companies who had also been given access, potentially compromising the data privacy of millions of users. Again, both software and human employees had access to user emails, with one executive from a third-party company saying that employees reading user emails was “common practice”.

Given Yahoos recent history with data privacy, this reminder that user emails may not be as protected as many think is unlikely to be good news for Yahoo, but whether it will cause a shift in policy remains to be seen.