Yahoo mail should add a new function

I really think they should add a new button: "select all unread mail"
Or better yet: "Mark all unread mail as Spam".

Because 4 out of every 5 days when I check my Yahoo mail, all my unread mail in my inbox are spam. As Yahoo mail's Spam guard doesn't really block Spam any better then a crude black list, they might as well provide an easier way to get rid of the Spam.