The purpose of these letters is to attract you to reply, or at least read them without blacklisting the address. At present, all major mailboxes have powerful anti-spam programs. When a stranger writes a letter for the first time, he is seriously wary and easily triggers keyword or attachment scanning. But if you reply, the anti-spam program will acquiesce that you are related to this person, and the letters sent to you from this address will not be intercepted or scanned less in the future, and people will give you a real blow after you reply to the letter. ...