You may have free Wi-Fi access at your favorite coffee shop, but you might not want to use it to check the balance in your savings account. If you're using an open wireless network, it's easier for hackers to intercept online transactions, passwords and other private business. "It's not the time to do financial business, your online banking or your shopping," says Marian Merritt, a Norton Internet safety advocate at Symantec, a manufacturer of security software.

That goes for websites that start with HTTP and HTTPS as well because you don't know how securely the coffee shop, hotel or other free Internet access point is set up. Hackers can set up "man in the middle" attacks to grab your passwords, card number and other information while you're on the public network. So enjoy the latte and save checking your credit card statement for later.