SAN FRANCISCO (AFP) - Google said on Friday (June 23) it would stop scanning the contents of Gmail users' inboxes for ad targeting, moving to end a practice that has fuelled privacy concerns since the free email service was launched.

A Google statement said Gmail users would still see "personalised" ads and marketing messages but these would be based on other data, which may include search queries or browsing habits.

Google Cloud senior vice president Diane Greene said in a blog that the free Gmail service would now follow the same practices as its corporate G Suite Gmail.

"Consumer Gmail content will not be used or scanned for any ads personalisation after this change," Greene said.

"This decision brings Gmail ads in line with how we personalise ads for other Google products. Ads shown are based on users' settings. Users can change those settings at any time, including disabling ads personalisation."

Privacy activists have long complained that the scanning of email contents amounts to unwarranted "eavesdropping" on users.

The internet giant earlier this year reached a settlement in a class action lawsuit in the matter, but a federal judge rejected the deal as inadequate.

US District Judge Lucy Koh ruled in March that the settlement was difficult to understand and "does not clearly disclose the fact that Google intercepts, scans and analyses the contents of emails sent by non-Gmail users to Gmail users for the purposes of creating user profiles of the Gmail users to create targeted advertising."

Danny Sullivan, founding editor of the online blog Search Engine Land, called the move a "big change" for Gmail, noting that the scanning of email contents "has been the biggest hit against the services since it began."

But Sullivan wrote on Twitter: "On the other hand, does it reassure consumers to know that Google has better info now about how to target them than by reading their emails?"