networks that require passwords. Wi-Fi networks that require a WPA key are orders of magnitude safer than networks using WEP passwords or no encryption at all. A WPA key is a password you enter on a security screen before you join a network, not one you're asked for in a web browser after you connect.
access your bank or credit card accounts. Don't even quickly check your balance through a public hotspot. Although your bank probably encrypts your online sessions, hackers can still view the name of your financial institution as you connect. Using that, they could send you fake "phishing" emails or set up a spoof network that mimics your financial institution's name. Wait until you're connected to your secure home or business network to access any financial accounts.
what you email. Consider your emails to be public postcards. Don't send notes that include business account information or client details that they wouldn't want shared. If you must email sensitive data, encrypt it with a Pretty Good Privacy (PGP) program such as Mailvelope.
off Facebook, Twitter, Amazon, and other personal accounts. Hackers could easily reel you in through your favorite sites. What looks like Facebook, Amazon, or Twitter to you could just as easily be a phishing site designed to harvest your account. Alternatively, hackers can employ session-hijacking methods, which involve stealing the authentication cookie while in transit - for instance, if you have a 'remember me' [set up], so you're not prompted for a password every time. By doing so, an attacker can pose as you without needing your password at all. If you must log on to these accounts, it's probably safer to do so via your smartphone instead of your laptop.
public Wi-Fi altogether. Use your laptop offline for work while you're away from the office whenever possible. Or if you truly need access to email or online accounts, set up a Virtual Private Network for your business. (Kitchen has used WiTopia, because it's easy and inexpensive.) These networks let you get online more safely than public Wi-Fi while away from the office by encrypting everything you do. An easier and possibly more secure option, albeit a costlier one ($25 or so per month), is using a mobile broadband adapter from providers like T-Mobile, Sprint, or Verizon. These gadgets let you create your own, password-protected mobile network wherever you go.
from Intuit Small Business Blog