An interesting snapshot of Grazr – see the full post for more details and examples/screen shots
When you sign up for Grazr's AlertRank service, you get a unique alertrank.com email address. You then change your Google Alerts to be sent to this new address. (Google lets you switch the email target easily.) When AlertRank receives the email from Google, it adds additional information before forwarding it on to you. That additional information gives you an indication of how "important" that alert is. It does this by showing the "AlertRank Quality Score" of the web site where the found page resides. The rank is a combination of Google Page Rank, Alexa Rank, and more.