Spam, Phishing and Suspicious Email
Many SPAM emails have instructions on how to be removed from the list. If you respond to these instructions they have a "verified" address -- an address that is known to go to a real email account. So, current thinking has it that you will end up on more SPAM lists rather than being removed. So don't bother. Besides more often than not the address is not a valid address.
A simple rule of thumb is that if you don't know the person who is sending you an email, be very careful about opening the email and any file attached to it. Should you receive a suspicious email, the best thing to do is to delete the entire message, including any attachment. Even if you do know the person sending you the email, you should exercise caution if the message is strange and unexpected, particularly if it contains unusual hyperlinks.
It's important to remember that, although some spam is simply annoying, phishing attempts are downright dangerous. Phishing attempts strive to get you to supply personal and confidential information or download malicious software. These actions lead to identity theft, virus, malware and more. The best defense against phishing attempts is education. Learn more about identifying phishing attempts here.