No, it’s not a food or drink. It’s del.icio.us, a social bookmarks manager. Here’s some details from the about page:
del.icio.us allows you to easily add sites you like to your personal collection of links, to categorize those sites with keywords, and to share your collection not only between your own browsers and machines, but also with others. What makes del.icio.us a social system is its ability to let you see the links that others have collected, as well as showing you who else has bookmarked a specific site. You can also view the links collected by others, and subscribe to the links of people whose lists you find interesting.
I remember first hearing about del.icio.us a long time ago, but never actually tried it until last night, and I have been using it pretty extensively since then. It’s already quite useful and very simple to do! Not only can I track the sites and pages I read and might want to refer back to later, but I can monitor keywords and see what other people have found too. You can check out my page at del.icio.us, and you can even subscribe.