Email forwarding -- Does not forward SPAM mail
I have a Yahoo email address forwarding e-mail to a different e-mail address that I use primarily. I NEVER check my Yahoo email because I assumed that ALL mail is being forwarded to that pointed e-mail address.
However, that is not true. The mail identified by Yahoo as spam does not get forwarded. I just missed a very important e-mail because Yahoo classified it as spam and did NOT forward the message to me. The Yahoo e-mail forward should forward ALL email regards if it thinks its spam or not.
This isn't the first time I noticed this, but this time it was a close call with an important e-mail. Luckily the person that sent the message, sent a follow up e-mail that was not flagged as spam that did get delivered to me.
If I can't rely on getting ALL of my messages forwarded to me then I'm going to have to eliminate any use of my Yahoo address.
You should include an option to have the spam included in the forwarding or not.

-
Ejnar Hansen commented
Have to agree - either Yahoo has to forward ALL mail or none. The problem is that we users has little or no control over what SPAM is. Have received more important emails and marked them as NON SPAM, but next time this company writes to me it is still being marked as SPAM.
Therefor the smart thing is to forward ALL mail and let us users manage this.
The second best solution is to have a setting "Forward SPAM? Yes/No"