Phishing is a huge problem. Thieves can create some amazingly realistic looking requests to log into various websites, capturing your password in the process. A basic understanding of how domain names works helps. If the linked website is yourbank.com, you’re safe. If it’s yourbank.somethingelse.com, it’s not. The last name before the .com is the highest level, pay no attention to anything separated by a dot prior to that name.