Just wanted to take a moment to congratulate Delicious on five years! Delicious was probably the first software many of us heard of that was using the idea of tagging, and now it's everywhere. I started using Delicious myself just shy of four years ago, both with a personal account as well as a shared work account at my former employer. That's where the idea for Pukka was born, after I (and several coworkers at our Mac-only company) got tired of switching accounts on the web all the time.
While many alternative services, most notably Ma.gnolia (which also works with Pukka) have also popped up and innovated in new and different ways, Delicious remains the grandaddy of them all.
Here's to five more years!