I am already familiar with del.icio.us, but have not used it regularly as yet.
My del.icio.us page can be found here.
I like the idea of the site, but I think one’s page can look quite messy with lots of links on it. I wanted to order my links alphabetically (the cataloguer comes out!) , but I can’t see a way to do that. My links are currently organised by last added to first added, which works fairly well.
I think that del.icio.us could certainly be useful for research. I like the idea of using tags to create a shared intelligence and share resources of interest.