In-coming e-mail that doesn't have my e-mail address, how is that?

[Ddrake9]

Although I've had my Verizon e-mail for a number of years now, something strange happened today. I received an e-mail that DID NOT have my e-mail address, but was sent to someone called "{edited for privacy}@verizon.net" from {edited for privacy}", and my e-mail address was not forwarded to or CC. So how did I receive it, and how do I stop this from happening again?

Further, my daughter's past e-mails from weeks ago, which she received at he verizon e-mail address,  were all sent to me today, even though she did not send them, or forwarded them. In fact, they look like regular e-mails, no "fwd" or "re" designations. Although her e-mail is under my account, why and how would this happen? As with "{edited for privacy", my e-mail address was not in the "to", "reply-to", "from", "cc", or "bcc".

Therefore, it seems as if there either has been a major screw up in the way Verizon handled messages today, or there was a security breach of some sort. Please advise on what I should to prevent this from happening again.

[tns]

There are of couse several ways.  Email recipients according to the SMTP protocol do not necessarily have to match those you nomally see.  And there is also an option called BCC even for the normal email users.