Privacy matters Google may have promised to stop scanning the inboxes of Gmail users for ad-targeting purposes last year, but it still lets third-party app developers read your private messages. The Wall Street Journal reports that while many of these companies use algorithms to trawl through your emails for keywords, some allow their employees to examine them, too.

The Journal highlights two companies that it says engages in this practice. The first is Return Path, an app that analyzes inboxes of users who have signed up for one of the free apps in its partner network using a Gmail, Microsoft Corp. or Yahoo email address. The publication claims that two years ago, Return Path employees read about 8,000 emails to help train the company's software.

Edison Software, a company that makes the Edison Mail app for iOS, was the other firm named. It's said to have let workers read "thousands" of emails to help train its app's "smart reply" feature.

While these kind of apps do ask for user consent, many of the forms don't make it explicitly clear that a human will be reading through your emails, not just a machine. Both the app makers say their practices are covered in the user agreements.

Google said that it provides data to outside developers who have been vetted and who have been granted permission by users to access their email. It added that its own employees may read emails but only in "very specific cases where you ask us to and give consent, or where we need to for security purposes, such as investigating a bug or abuse."

To find out and edit which third-party apps have access to your Gmail account, head to the My Account page and login.

Edison said it has since stopped this practice. "Our email app was mentioned in the context of our engineers having in the past the ability to read a small random sample of de-identified messages for R&D purposes. This method was used to guide us in developing our Smart Reply functionality which was developed some time ago," CEO Mikael Berner said in a statement. "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."

Return Path also defended its actions. "As anyone who knows anything about software knows, humans program software - artificial intelligence comes directly from human intelligence," it said. "Any time our engineers or data scientists personally review emails in our panel (which again, is completely consistent with our policies), we take great care to limit who has access to the data, supervise all access to the data."