The news goes back to July 2011, when Microsoft launched a small advertising campaign called The G-mailman. Basically, what Redmond criticized was that Google read the emails of its Gmail users to personalize advertising results. That reading is still active today, but through a brief statement, the Mountain View giant confirmed that it will be disabled before the end of the year. Of course, general advertising on the service will not disappear, and personalization will depend on other parameters.
The saying goes that "if you don't pay for something, you are the product". More than once its validity was doubted, however, when it comes to online services, there is not much room for maneuver. Platforms like Google, Facebook and Microsoft offer free services in exchange for constant data collection used to personalize ads and improve those services in the process. The problem is when collection crosses a limit that makes us feel uncomfortable, and in the specific case of Google, the example is Gmail. Every email sent and received is scanned "in content and context" to present more relevant advertising to the user. Google had to face several lawsuits and disable scanning in its educational apps, but now that will expand to the rest of users before the end of the year.
What Google seeks is to unify its personalization methods between conventional Gmail, educational apps, and the commercial section of its G Suite platform. In all cases, advertising will be based on specific parameters that the user has configured within their account. Those parameters can be checked through this link, which also includes the possibility of disabling personalization completely. Personally, I believe it is preferable to limit results to a couple of manually entered categories, rather than letting algorithms deliver very low-quality results.
Even so, email checking in Gmail will continue to index content, apply filters, detect spam, and eliminate malware. At the same time, the Smart Reply feature in the mobile version of Gmail (introduced in mid-May) analyzes the context of each email and offers a quick automatic response.