No, they do not read your email, they're very clear about this, that is mostly FUD pushed by privacy providers who lack ethical marketing standards.
We do not scan or read your Gmail messages to show you ads
If you have a work or school account, you will never be shown ads in Gmail.
When you use your personal Google account and open the promotions or social tabs in Gmail, you'll see ads that were selected to be the most useful and relevant for you. The process of selecting and showing personalized ads in Gmail is fully automated. These ads are shown to you based on your online activity while you're signed into Google, however we do not process email content to serve ads.
To remember which ads you've dismissed, avoid showing you the same ads, and show you ads you may like better, we save your past ad interactions, like which ads you've clicked or dismissed.
The place where Google makes the money is on the sites you visit with Google Adsense and your search terms being associated with a logged in Google account. Most people want to stay logged into their email (and thus their Google account), so that's where the behavioral/adsense analytics comes in. Much fewer people use email clients these days.
I don't. I just run
prefsCleaner
each release and thenupdater
.