Twitter's Mobile Ad Shop Using Verizon's ID to Track Users - ProPublica

Visit the full post from your mobile device to check for a tracking code

"Twitter's mobile advertising arm enables its clients to use a hidden, undeletable tracking number created by Verizon to track user behavior on smartphones and tablets. Wired and Forbes reported earlier this week that the two largest cellphone carriers in the United States, Verizon and AT&T, are adding the tracking number to their subscribers' Internet activity, even when users opt out."

Twitter's Mobile Ad Shop Using Verizon's ID to Track Users - ProPublica