This article is from 2005. Technologies and best practices have evolved since then.
You can tag items for others. To do so, use "for:username" where username is the name of the user you want to send the item to. You can see items tagged for you at http://del.icio.us/for/ -- it'll redirect to your own page, which other users will not be able to see. Update: Just a quick note that this feature is not really useful... I just wanted to say that.