Yahoo Attempts to Fight Phishing With Sign-In Seal
I clicked on it and was redirected to a page that read the following:
Protect users on this computer against password theft with a sign-in seal.
A sign-in seal is a secret message or photo that Yahoo! will display on this computer only. Look for it every time you sign in to make sure you're on a genuine Yahoo! site. If the message, photo, or colors are different, you may have landed on a phishing site.