Yahoo, which is now a part of Oath Inc., has been reported to persist in the sale of user email data to advertisers. This practice, which Google for one has sworn off in the past, may include the scanning of information concerning purchases sent by online retailers.
https://www.notebookcheck.net/Yahoo-is-still-profiting-off-your-email-data.327202.0.html
Linked to millions of dormant, abandoned accounts I hope. I know very few people who still use Yahoo Mail as their main email account.