Passwords are used very widely for authentication to Web and other IT services/networks. The only problem is that if someone gets hold of your password then they can easily use it to "borrow" your identity. It is therefore important to avoid passwords that are too simple such as birthdays, place of birth, children's birth dates, nicknames etc. The best way to do this is to write them down somewhere safe but don't write down what the associated Web site is. You should also change your passwords regularly and keep your anti-virus and anti-spyware software up to date so as to avoid criminals downloading malware software that can read what you are typing on your keyboard.

For more on this subject, see also, "How do I choose a good password?" and "Are passwords safe?" or click the tag words for password security, malware, phishing and identity theft.