To preserve your bookmarks, you can export them. The result will be a webpage that looks like a list of links. Your descriptions will be visible, but not the subject tags. Tags are captured by the export, they are just not visible (right click and look at the Notepad source information). However, you will no longer be able to reach any bundles.
Although a number of alternatives have been mentioned, none yet appear to offer as many features. Possible options mentioned by others, but I have not studied any of them:
http://historio.us/
pinboard.in
http://www.diigo.com
http://wonderpage.com
This is an interesting article on Web 2.0 sites in general.
Websites referenced:
https://secure.delicious.com/
https://secure.delicious.com/settings/bookmarks/export
http://www.readwriteweb.com/archives/rip_delicious_you_were_so_beautiful_to_me.php
Websites referenced:
https://secure.delicious.com/
https://secure.delicious.com/settings/bookmarks/export
http://www.readwriteweb.com/archives/rip_delicious_you_were_so_beautiful_to_me.php