FWIW this is how I saved URLs originally; when it got unmaneagable I built muxway and then del.icio.us. The notes became tags as they were often a single word. Hash because it was a comment.
Interesting, did factoryjoe know that when he proposed hashtags for Twitter? There weren't hash marks in the del.icio.us interface but I don't remember if muxway had them or not.
I still have an XML dump of my del.icio.us bookmarks that I haven't merged in. The linkrot rate is pretty high.