I colleague in the SWEO group (I think it was Paul Miller, I am not sure) drew my attention to the BibSonomy service. The service is pretty much along the same lines as del.icio.us. One can have bookmarks, share it with others, add tags, etc, etc.
So why bother? Well, the nice feature of BibSonomy is that it combines the traditional shared bookmarks with a more rigorous storage of bibliographical data. Ie, one can store bookmarks just like on del.icio.us, but one can also store bibliographical references for books, journal articles, etc, tagged the same way as bookmarks. For people working in, e.g., research where bibliographical data are necessary, this is a real plus. And the same social networking works for these entries, too. Ie, my (publicly visible) entries tagged with “accessibility” lists both my (few) bookmarks and the literature entries side by side. It has the usual goodies (RSS feeds, public vs. private bookmarks, etc) that I use at del.icio.us; one can also have a BibTeX and EndNote dump of the publications, as well as RDF formats.
I am seriously thinking of moving to this service instead of del.icio.us… To be seen.
(B.t.w., it has an extra service of importing your del.icio.us entries. An easy way to start with it…)