"Undisclosed Recipient" emails from a person who has never ever sent me a personal note.

Some people have a group name which includes most of the addresses they have and they send anything of interest to everyone in that group name...

Sometimes when I receive such an email, I know that the person who sent it was just broadcasting and the email really isn't something the author thinks would be of interest to me.
EXAMPLE: I got an email addressed to "Undisclosed Recipient": It was an article telling people who wish to, how to gain weight. If you know me, that email was not applicable to me at all.

I have chosen to send emails to several people in a single email addressed to "Undisclosed" which is not a group address...then I BCC people from my address book that I think will specifically benefit...for that email.

SO! You know this email is specifically meant for you...and no one else sees your address in the TO: or CC: block (to maintain any privacy for your address).

Each time I send to Undisclosed, I select exactly to whom it will go...EACH TIME. It takes a minute or so extra time for me, but it avoids sending you an email about how to gain weight (if you are even slightly as heavy as I am - grin).

I urge you to consider a similar method of your own. Why? Because broadcasting to everyone in your address book or to a large number of them, indiscriminately, is like telling a story out loud in the middle of a bus station :
(1) some people don't think you are talking to them and don't listen
(2) some people disregard any email not specifically addressed to them (unless they know you have purposely selected them)
(3) some people broadcast everything they get in email as a forwarded item
(4) persons who you really want to read the email for important information often put off reading such emails.
(5) I grow weary of receiving emails addressed to "Undisclosed Recipient" from people who I would like to think are thinking of me, only to realize I was put on a distribution list long ago; the sender is just doing a "quick and dirty" mailing to a group that hasn't been updated and I've really been forgotten (which is okay, just update your group listing and quit bugging me). I have received dozens of Undisclosed emails from a person who has never ever sent me a personal note and to whom I have not written in years.