I have found a couple of interesting links on the SLL2.0 page --one is
5 Ways to Mark Up the Web . This article discusses various ways to annotate web pages and share your thoughts with a work group or class--I've tried Trailfire, and I can see how it would be very useful in the classroom because you could have students follow your trail from site to site and your Trailfire "notes" could help them know what to study/where to go on each page. Particularly useful with younger students or special needs students. The problem (as always) is that you have to sign in to use it, and we'll probably not be able to do that at school.
As for the use of Del.icio.us at school, of course I see how the social or interactive aspect of the site is an added value to other more "traditional" sites like MyBookmarks , but frankly, I'm not entirely sure we are able to get to it through our school filter either. I'll have to check next time I'm up there. I suspect that many of these Web2.0 tools that we're looking at in this program are a half-step ahead of what our IT department is ready to allow us to do at school. I think it's getting less restrictive bit by bit in our district, but I'm still stymied many times when I want to use a cool new tool and then find that it's filtered out at work.