Phishing
Phishing is a whole different category. A mail arrives, from your bank, so it seems, tov erify your account (click to enlarge) 
Unfortunately this mail wasn't sent out by your bank, but by someone trying to find out your account settings. The url shown is not the url which it is linking to, even worse, when you click on the link the url in your browser may show the url from the mail, but 'behind' that address is the real address, so it's not your bank. Trying to find out if the mail is real isn't hard. Most protection programs detect phishingmails but you can do even better.. No company will EVER ask you to confirm your account. Once you have an account setup they will NEVER mail you asking you to confirm your account. So, when you get a mail (below is another example) delete it, or contact the company to confirm whether the mail is real.