Social bookmarking site del.icio.us announced last month that it will give people the option to make bookmarks private — for “those antisocial types who doesn’t like to share their toys.” This a sensible layer to add to the service. If del.icio.us really is to take over the function of local browser-based bookmarks, there should definitely be a “don’t share” option. A next, less antisocial, step would be to add a layer of semi-private sharing within defined groups — family, friends, or something resembling Flickr Groups.
Of course, considering that del.icio.us is now owned by Yahoo, the question of layers gets trickier. There probably isn’t a “don’t share” option for them.
(privacy matters 1)