I really like what the folks over at juice analytics put together to visualize del.icio.us posts over time. They call the post "My year in attention (and yours)".
I still think the idea of using del.icio.us to track attention is spot on. With del.icio.us, you're not only tracking what you are paying attention to over time, but you're also adding dimension (tags) to your attention that should be worth something to marketers (and not just Yahoo's marketers). Del.icio.us is well positioned to be a very big leader in the attention market.
On a slightly different topic, but still related to analytics, check out what juice analytics did with a flash-based representation of data over time - it's also mocked up using Excel. Clever.