Using free wireless networks (whether they're open or password protected) increases your risk of data theft. Anything you transmit over such a network — including personal information like credit card numbers, photographs or other potentially sensitive materials — can theoretically be intercepted by hackers. That's why it's important to use only encrypted websites (those that start with https:// instead of http://). This makes it much harder for people to capture your personal information. Additionally, you may want to consider a service like Privacy.com, which allows you to create virtual credit cards that can be assigned spending limits and/or locked to a specific merchant. That way, if a hacker does manage to snatch your data, they won't be able to do much damage.