Okay, I must be working too hard. I missed that del.icio.us has added sparklines to the most popular listings. If you don't know what a sparkline is, term coined by Edward Tufte, the device is a small graphical data display that takes on word like properties. You start to recognize certain sparkline shapes as words that support discussion of data. Think of how a flatline on an EKG says "boy I was daid!"
Anyhoo, this is a welcome addition in determining why a popular link is actually popular.