This sounds very, very useful:
Microsoft Research’s Community Technology presents SNARF, the Social Network and Relationship Finder.
SNARF was built around the notion that social network information that is already available to the computer system can be usefully reflected to the user: a message from a manager might be seen differently than a message from a stranger, for example. SNARF applies this idea to email triage: handling the flow of messages when time is short and mail is long.
The SNARF UI is designed to provide a quick overview of unread mail, organized by its importance. The UI shows a series of different panes with unread mail in them; each pane shows a list of authors of messages. Clicking on a name shows all messages involving that person.
People use a variety of strategies to handle triage; there is no single “best” ordering of email messages to produce an optimal outcome.
SNARF gives the user the freedom to build their own ordering. Each person in their inbox is assigned a set of meta-information: “number of emails sent in the last month,” for example. These metrics can, in turn, be combined to create an ordering across all contacts. For more information, check out the CEAS paper on SNARF.
I don’t believe there’s a “magic bullet” for organizing e-mail, but this concept has a lot of potential for helping to prioritize interesting stuff. I’m especially interested in comparing it with ClearContext.
Ed Bott 
I tried it yesterday. Like you I was interested to compare it to ClearContext.
I uninstalled it today. The problem is that it displays seperately from Outlook. I do not need two places to look. ClearContext wins as it displays within Outlook.
One final thought, I did like the summary window showing unread emails addressed To or CC’d to me by sender, but again the seperate window from Outlook made it less useful to me.
SNARF is based on a nice idea and attempts to solve a real problem. However, I don’t think that email overload can be solved purely by brute-force technology such as this. As human beings, we behave unpredictably and inconsistently. In today’s fast-paced world, any tool which analyzes what I did yesterday will be hard-pressed to truly understand what my priorities are right now. I don’t want to ramble on here, so if you’re interested, go to http://itzy.wordpress.com/2006/02/02/the-cow-and-the-butterfly-conspire-against-email-overload/