Contact list spam
If we detect that an email address in your contact list is sending you a message that looks like spam, we'll let you know by highlighting it as spam in the inbox. If you know that the email is safe, just click "It's safe" and we won't bother you again. For some spam in your spam folder or inbox we will show helpful messages to let you know why we put the mails there and allow you to take corrective action.

If you have any doubts, click "Remove sender and mark as spam" and the message will be moved into the spam folder and the sender will be removed from your contact list. If you'd like to reverse the action, you can do so by going to your spam folder. Click "It's not spam" on the message to move it into the inbox, and future messages from this sender will be delivered to the inbox.

Unsubscribing
When you mark a message from a mailing list as spam and we trust the sender, you will be given the option to unsubscribe rather than marking it as spam. Select Unsubscribe and you will no longer receive any messages from the mailing list. Selecting Report as spam will mark the message as spam and move it into the spam folder.
 

If we detect that an email address you'll receive replies to is anything other than the one you're sending the message from, we'll let you know with a little alert on the top of the message. If you've set up the reply-to function in your email, then there's no worries! But if you didn't set that up, you should secure your account immediately.

If we detect that the email address sending you a message looks "phishy," we'll let you know by calling it out. If you know that the email is safe, just click or tap "It's safe" and we won't bother you again. If you have any doubts, click or tap Report and we'll take care of it from there.

Mail Forwarding alerts are only available with a Yahoo Mail Plus subscription available for US only or Yahoo Mail Plus subscription.
When you log into your account after Mail Forwarding has been set up, you'll get an alert notifying you that auto-forwarding has been set up. If you enable it, there is nothing that needs to be done. If you did not set this up, click or tap on "Disable Forwarding" and follow the prompts to disable it and change your password.