Epsilon won't specify which of its 2,500 clients were affected, or how many customers' e-mails were stolen, but has put together the following list: Kroger, TiVo, US Bank, JPMorgan Chase, Capital One, Citi, Home Shopping Network, Ameriprise Financial, LL Bean Visa Card, McKinsey & Company, Ritz-Carlton Rewards, Marriott Rewards, New York & Company, Brookstone, Walgreens, The College Board, Disney Destinations, Best Buy, and Robert Half Technologies.

What's the risk for people who use any of these services?

You may notice an increase in e-mail spam and phishing attacks, which aim to gather passwords and other sensitive information from their targets. Due to the nature of the Epsilon breach, these attacks may address their targets by name, making them more convincing.

Was any other information exposed? Should users change all their passwords and cancel their credit cards?

No. According to Epsilon, no other personal information was exposed besides e-mails and names. Law enforcement and individual companies are doing their own investigations, but unless you've got , your money should be safe.