I think it depends on who you are and what you want from the web? E.g. I've just spent three years finishing a masters and being able to bookmark hundreds of articles which I used for research was invaluable. Sure, you bookmark in your browser, but I use three machines daily and numerous browsers. Having access to my bookmarks anywhere I was studying was very useful. I think the millions of users on various bookmarking sites is testament to the value of bookmarking.