Alright, I've converted. From spurl to del.icio.us. The interface is so much more FUN to use and visually simple. Spurl's bookmark isn't as RESPONSIVE as deli.cio.us, and because when I'm browsing, I want to bookmark and be on my way.
But the thing that won me over was tab completition and suggestions of popular tags. Of course! Folksonomy would work much better if there was a convergence of names for things. Some things are easy to name, but articles and webpages are multifaceted and talk about various things. And sometimes, what they are do not get mentioned in the article. Del.icio.us does that, and Spurl does not. And this cuts down on my bookmarking time, and lets me get back to web browsing.
And while this is not the catalyst, but I had been thinking about a 'new' widget, a command line w/ tab completion widget, where there is a textbox, and an icon or text window below. It would work much like del.icio.us's tab completion or linux's command line tab completion.
Essentially, this is a replacement for the pulldown menu, which I never found particularly fun to use, since you have to aim more carefully to select options, and usually, when you're filling out forms, your hand are by the keyboard filling out text fields anyway.
It would be more fun, I think, if the tab completions showed icons or pictures tagged a certain thing, so if you were looking for a searching functionality, typing 'search' would bring up all icons related to searching tools, and while you're typing 'sear', it would bring up all icons related to functions that start with 'sear-'.