Have Efforts to Create a Do-Not-Track List Derailed?

The brightly colored running shoes stare back at me from my computer screen. They’ve been following me from website to website — ever since I clicked on them while browsing an online store the week before. The shoes aren’t supposed to follow me like this. I’ve set my browser to send a message to each website I visit expressing my desire to opt out of such tracking. But here come the shoes again. And again. What happened to the online …