Two-factor authentication, sometimes called two-factor verification, is a system in which you have to enter a password and then receive an SMS (text) message or email through which you verify that you actually tried to sign into your account. I use this on every service that offers it including my Google account and all bank accounts. This is great because if someone does try to sign into one of my accounts from a computer or phone other than mine, I immediately get a text message. My friends Lee and Sachi LeFever at Common Craft have a great video that explains two-factor authentication. You can see that video here.
Unfortunately, Netflix doesn't currently offer two-factor authentication to protect users' accounts. Fortunately, while it's massively inconvenient to have your Netflix account hacked there isn't too much damage that a hacker can do with your Netflix data. The best thing that you can do to protect your Netflix account is to use a strong password that you only use on Netflix. Again, Common Craft has a good video about creating strong passwords.
For help in creating a strong password consider using a tool like Wolfram Alpha's password generator.
Common Craft videos can be reviewed online for evaluation purposes. To use embed them into a blog as I've done requires a membership (which are very reasonably priced).
Disclosure: I have an in-kind relationship with Common Craft.
