Those who upgrade can opt out of contextual ads through Yahoo’s Ad Manager. Yahoo bluntly tells users who refuse its new policies that they should either download their mail to another IMAP client, or close their account. Premium Mail Plus users who want to cancel their accounts can get a prorated refund.
Some are labeling the switch an aggressive invasion of privacy. An anonymous Jottit user writes “Yahoo can now openly troll through email for personal information that it can share or hold onto indefinitely. Gay and haven’t come out yet? Yahoo knows.”
However, as commenters on Hacker News note, Gmail has long scanned your email to show you related ads. Even if you use a system like StartMail that doesn’t scan your messages, the system your conversation partners use might not be so hands-off. And as many warn, anything you send in an email could end up public, so keep the naughty stuff off the web.