How to opt out of Yahoo Mail's invasive data scanning - The Verge
Report: Yahoo scanned users' email for U.S. intelligence agencies
Yahoo email surveillance: who approved the secret scanning program?, Yahoo
Yahoo and AOL are said to scan emails for data to sell to advertisers
What Yahoo's NSA surveillance means for email privacy
Yahoo Reportedly Spied on Millions of Mail Users
Ex-Yahoo Employee Says Spy Program Created Privacy Risk
Yahoo built spying software after US govt request
Delete Your Yahoo Account