What if your telecom company tracked the websites you visit, the apps you use, the TV shows you watch, the stores you shop at and the restaurants you eat at, and then sold that information to advertisers? In theory, it’s possible, given the stance Washington is taking on online privacy. Lawmakers on Tuesday voted to overturn privacy rules that required telecom companies to get customers’ permission before sharing their web-browsing and app usage history with third parties.

The White House said Wednesday President Donald Trump intends to sign the measure into law. Undoing the rules, which had been adopted last fall by the Federal Communications Commission but hadn’t gone into effect, is a boon to Verizon Communications Inc., VZ -0.42% Comcast Corp. and AT&T Inc., T -0.08% which are all in the process of building data-driven digital ad businesses to complement the broadband, wireless and TV services they offer. READ MORE