This is a common problem with a very few e-mail account suppliers.
The next time you get one of these simple little e-mails that seems to be from somemone you know, check their e-mail address. A LARGE percentage of them will be from an AOL, YAHOO or MSN e-mail account. (There may be a couple more that I don't recall off hand.)
It means their e-mail account at the e-mail provider ( AOL, YAHOO, etc.) has been hacked and is being used to send out the junk. If you notify the real person, tell them they need to (at least) go to their e-mail account and change the password.
The second thing you should ask them to do is get a REAL provider instead of the junk that is AOL, YAHOO, etc!

Bill