What is Linkroll?
Linkroll is a free link blogging service.
It works on a group level by enabling you to browse other user's bookmarks, and subscribe to users and link categories that appeal to you. Using the subscribe function (requires registration) you can create a unique view of all bookmarks related to things and people that interest you. Conversely, there is also an ignore function...so you can ignore particular users or link categories which don't appeal to you.
More info at http://www.linkroll.com/index.php?action=about