I can definitely see the value of a Delicious network, kept in some kind of organised fashion, for a group of people who share interests. If I'm honest, I wouldn't add me to my network, unless I had an interest in randomness gathered on the internet. Actually, put like that, maybe my bookmarks are more entertaining than I think. Through my copious RSS feeds, I gather all kinds of random and interesting webpages. Like people who have a quotation or a song for every occasion, I usually have a webpage for every occasion, or I know where to get one (usually Lifehacker). It's been useful more than once, and I suppose it might be useful to others as well.
Generally though, I would think Delicious networks are best for shared interest groups, or for trusted sources or where you're sure the tagging is consistent. So if you need to stay up to date with Law, adding us to your network so you always know when the latest books on your subject come in is hugely valuable. It might even be a good way for students to share useful websites between themselves. If they're using other collaborative tools (eg Googledocs), it might be a good place to keep links to the various documents and articles for a project - you could just add the project tag and other members of the group could find it.
On the other hand, just adding people at random probably isn't such a good idea. Yes, this is going to be a recurring theme in this blog, but the principles of provenance and authority don't stop applying just because you're on the internet. If anything, with Web 2.0 tools, critical thinking and evaluation are even more important. Either that, or you just accept that you're going to pick up 90% rubbish (you should see some of the things in my GoogleReader), but it's worth it for that 10% gold.
