Employees at third-party developers were permitted to operate on real Gmail emails to improve their systems, a practice described by one former employee of third-party dev eDataSource as a "dirty secret".
Insights gained – such as the best time to send a marketing email, and who is most likely to open it – would then be sold to e-marketers.
Gmail has a monopoly position as a free webmail email provider, with over 60 per cent of the market. That means even non-users will find their private communications on Google servers, if they're communicating with a Gmail user.
Kill Google AMP before it kills the webREAD MORE
As we noted last year: "Google's not going to stop pushing targeted ads – it'll just get the information to do this from your searches, YouTube watching habits, Android phone and every time you use any other Google service. And Google will still be doing some Gmail scanning to offer up its Smart Replies suggestions at the end of the messages."
If the emails were indeed being read without the author's explicit and clear consent, this would likely be unlawful under GDPR. It's worth noting that both Return Path and Edison told the paper that their practices were covered by their user agreements.
Again, if no consent were obtained, it would contravene Google's own developer agreement, which requires explicit opt-in consent when a user's "non-public content is obtained through the APIs".
Google has said it manually vets each applicant to use the API to weed out known abusers, but sources told the WSJ that Google was lax about enforcing the rule.
In a statement published on its website, Return Path founder Matt Blumberg said his firm had co-operated with the reporter but expressed dismay that the report was "extremely and somewhat carelessly selective".
"Unfortunately some companies take personalization to an extreme, but an online experience devoid of personalization would feel oddly generic to the average consumer," he wrote.
And without third-party API access, the giant platforms would exclusively reap the benefits of scale.
Google has been accused of turning Gmail into a walled garden by introducing new features exclusive to Gmail. Google has argued that nothing is proprietary, and like AMP, it's all based on open-source and open published standards. However, like AMP, given Google's market dominance, it's a standard from which only Google can really benefit. ®