Del.icio.us turns the simple act of bookmarking a website into a public activity, creating a shared community. In doing so, it enables users to show off things they have found, find new interesting places on the web, and discover other people who also find interesting material.

By focusing on a user’s actions (the actual act of bookmarking) to capture intent rather than ratings or reviews as in a collaborative filtering system, del.icio.us can be to painlessly integrate into the user’s daily habits. Since it provides a sort of external memory as well as access to other user’s bookmarks, it is both directly and indirectly beneficial. In addition, an innovative organizational schema allows the users to quickly add a few short words, called “tags”, to both describe and categorize new entries. The dynamic creation of tags allows for an amorphous, shifting, and developing zeitgeist to evolve, thus freeing the user from the strictures of traditional “tree-based” categorization systems. A bookmark can belong not just to one idea-space, but to any number of synergistic or even seemingly contradictory ideaspaces.

Arguably, “bookmark” is the wrong word for what del.icio.us enables. Like posters on city blocks, one can watch ideas infect virtual neighborhoods and proliferate, as first one user, then another, then many more, attach their imprimatur to a URL (although of course one must not mistake this for approval of their contents—people are just as passionate about that which they hate as they are about that which they love).