Visualizing tag clouds
I have never really got into the habit of using del.icio.us to bookmark and tag items. Maybe this is because I don't bookmark anything anymore. All of the bookmarks in my browser are ancient and essentially useless. Some of this is due to autocomplete. If you can type two characters and get the link you want, why bookmark it?
Also, I have a partial substitute in Bloglines, which provides links to the home page of many sites I'm interested in and new content on those sites. Since I tended to bookmark home pages in my browser, this really isn't much different.
The ability to see where my attention has been focused over time is huge for me. How helpful would a reminder of what you were looking at when be in assembling your year-end accomplishments for your boss, for instance? Or maybe even to figure out what accounts to charge your time to? A great addition would be the ability to tag your email and calendar items, so you'd be able to see something closer to the full scope of your work. Unfortunately, in a corporate environment, email retention policies would likely make this an impossible dream.
Another more obvious benefit is in addressing my feed reading backlog by tagging and bookmarking interesting items.
The power of well-done visualizations is an immense. The need for cheap, effective tools in this area is nearly totally unmet.