Trailfire is an online tool to create a list of related sites such as for Shakespeare, Algebraic Equations, Writer's Craft, Weather, or other. The list can be annotated for directions or explanation of the site's usefulness. Two views are given, one is a slide show-like display where you view each site with a message box of annotated comments, or in a summary view where you see at a glance the site links.
This could be as useful as Delicious in that students and staff can view each site with directions for a task (in case of the students) or explanation of resource (in case of the staff). The slide view enables web site viewing as you read the annotated comments.
Here are two examples:
Students studying Weather
Trail link: http://trailfire.com/cydenning/trails/39383
Teachers studying Project-Based Instruction
Trail link: http://trailfire.com/librarytigger/trails/37472
When setting up such lists, it's important to check for broken links so as to keep the list up to date.