It's a simple matter for a hacker to steal data from an unencrypted Internet connection. That's why banks and financial institutions all use encryption.
However, not every website uses encryption. And some sites stop using encryption after you've signed in. This leaves you vulnerable and open to hackers and malicious viruses online.
Make sure you're always protected with the browser add-on HTTPS Everywhere. It's easy to install and it keeps your communications secure with major websites. Adding it to Firefox, Chrome or Opera is as easy as clicking which browser you use.