Delicious, as the sort of "grandfather" of social bookmarking sites, is a great resource if you 1) have friends or people that you'd want to share bookmarks with...2) you don't mind a monochromatic theme...
I actually really like Delicious BUT sometimes, my eyes go crazy because of the plain old black and white theme...I think that makes it hard to find information. I also really like that the website streams the most recent and most popular bookmarked websites...
Unfortunately, faves has gone out of business as of the 25th of May. It had many of the same features as delicious but I guess it just couldn't compete.