After having played around with Shadows for around a year I'm now back with del.icio.us . The shadows thing was good, but the biggest problem was that shadows unlike del.icio.us does not allow me to export my bookmarks. This is vendor lock in and very very bad. Something which should not be encouraged with any Web 2.0 startup. So long guys and thanks for hosting my stuff. If there was atleast a sync-with-del.icio.us feature I would have stayed. I wish there was a "delete" feature in shadows so that I can delete my bookmarks, but there doesnt seem to be any.
If anyone is planning to move back to del.icio.us from Shadows, use Flock , configure it with your shadows account and get all your bookmarks, then change to the del.icio.us account and Flock will sync all your bookmarks with del.icio.us and yes, it will take care of the existing tags and duplicates which exist on de.icio.us . Oh! and check out Flock 0.7.3, it rocks!