The Wall Street Journal spoke to a number of developers and found that "thousands" of messages had been read not by algorithms but by employees, something which Google says is perfectly fine and allowed by its policies.
The report said at one point, Return Path workers read about 8000 unredacted emails to train their company's scanning software. Some allow people to write emails in special fonts, or to make it easier to find images to send to others, while others make it easier for people to organise their emails into folders. Google pointed us to Security Checkup, which lets you revoke access from any third-party apps you've given access to, and more recently started flagging apps that ask for a large amount of data.
Last year, Google had assured that it would stop scanning the inboxes of Gmail users for information that helps it offer personalised advertisements, announcements, shopping and travel deals etc. "We have since stopped this practice and expunged all such data in order to stay consistent with our company's commitment to achieving the highest standards possible for ensuring privacy". The increased scrutiny follows the Cambridge Analytica scandal, the now defunct data firm accused of misusing the personal information of more than 80 million Facebook users in an attempt to sway elections.
In Google's case, outside developers must pass a vetting process, and as part of that process, Google makes sure that they have an acceptable privacy agreement. While many of these companies in question utilise machines to go through users emails for keywords and phrases, some of them have it done manually by their employees.
They include Return Path, a company that collects data for advertisers, and email organisation tool Edison Software.
The other is Edison Software, an email management app.
While these kind of apps do ask for user consent, numerous forms don't make it explicitly clear that a human will be reading through your emails, not just a machine.