I received information from one of our clients that Verizon is now included in the list of companies affected by this problem.
CNET has a great article on who Epsilon is and why they have your data - please read as it's very eye-opening.
CNET's Video Podcast "CNET to the Resecue" yesterday dedicated nearly its entire episode to this issue and goes over some recommendations for affected users that include changing the email addresses and passwords that are used for those affected companies.