US lawmakers press online ad auctioneers over user data

A bipartisan group of US senators has sent letters to major digital ad exchanges, including Google and Twitter, asking whether user data was sold to foreign entities who could use it for blackmail or other malicious ends.

In the real-time bidding process to decide which personalized ads a user sees when a web page loads, hundreds of businesses receive a user’s personal information, including search history, IP address, age and gender.

Questions about the sale of data gathered during the auction process were also sent to AT&T, Index Exchange, Magnite, OpenX, PubMatic and Verizon, according to the office of Senator Ron Wyden, a Democrat representing Oregon.