Yahoo's sign-in seal

Yahoo mail (i dunno about the rest of their services) has implemented sign-in seal which is quite similar to Bank of America's sitekey concept. The idea is to authenticate the site to us. When I see the Yahoo Seal which I had already set (it is a phrase or a picture that I set), I know and am sure that I am accessing an Authentic Yahoo site. Hopefully, people set some Strong, hard to break seals which would help fight phishing.