How to see the hidden mail ids in the “to” address bar?

Meghana S: How to see the hidden mail ids in the “to” address bar?
I have received a mail in my gmail inbox, where, in the “to” address bar i am not able to see any mail ids including mine!
How do i get to know who all are the mail recipients?
How does this happen?

Answers and Views:

Answer by John Reid
I get a lot of mail in the same way. Sometimes it read “To undisclosed recipient”.
I send all of my mail as blind carbon copies. That way, the spammers cannot pick up the address.

The bad news is, that if you forward the email, all of the first addresses will show up.