Having looked at Delicious during class I have to say I like it...but not alot. I think it has more use as a personal tool rather than for any use in the learning environment. I like the fact that all my bookmarks are there in one place though
Students could use this on their own initiative in their own time as they would have a shared interest i.e. the course. I dont think that this could be done directly in conjunction with the Department though as there is no way of monitoring it properly and some people, even now, are reluctant to share even their email address with other students on our course.
I can't really see it in the workplace.
As with other tools, there is a certain element of self-reliance and motivation in making sure that you keep up to date with all of them. Its up to you to add things to your Reader and keep your blog going (even when pushed for time) .