From Web CEO:
EmailTray lets you focus on important mail only. It guaranties you will see high-priority messages in real time. It receives emails from all accounts (OutLook, Gmail, Yahoo! Mail, Hotmail, AOL Mail), classifies email by importance, and shows important mail from all accounts on one list. EmailTray intelligently determines email importance based on user email habits and interconnections between senders. EmailTray also notifies you when it gets a top priority message only. It rescues good mail from Spam and returns it to a priority folder if your antispam program has trapped an important email.