Software vendors can create services combined with features provided by Google's Gmail, such as linking the user to the service with their Google account. According to a statement, companies and developers of each company can access the emails received or sent by the Gmail account.
In particular, the report was talking about 2 applications. One of the two is Return Path, an application that analyzes Inboxes and collects information for vendors. Prior to 2 years, Return Path employees read about 8.000 emails to create and train their current platform.
The second application is called Edison Software, and helps its users keep their emails more organized. To train a "Smart reply" function, it is reported that employees read thousands of emails from platform users.
Return Path reported in one blog post "Every time our developers control emails on our panel (which is fully compatible with our policies), we make sure we limit who has access to these data, supervising the slightest traffic."