Virtually every American is making at least one mistake protecting their data, says author Joseph Steinberg of "Cybersecurity for Dummies." A survey of more than 2,500 adults by Bankrate.com finds four in five people reuse passwords, while the next most common mistakes are saving passwords on a phone or computer and saving payment information on a device to make shopping faster and easier. Other behaviors Americans admit to doing include: using an ATM somewhere other than a financial institution (28 percent), carrying a Social Security card in a purse or wallet (26 percent), throwing away or recycling personal documents without shredding first (23 percent), and posting their birth date on social media (15 percent).