One of the really great things about the WWW, as opposed to the Internet in general, is that the Web separates the concept of naming from everything else. A URL is bit of text that names a resource. You can type it. Except for some long URLs used by banks and in ecommerce, you can often even remember it. But most importantly, you can include the text in some other technology such as an email, an instant message, a calendar invite, a Web page, or even in a book or piece of paper. It can be sent and stored. The URL can be transmitted through this separate non-WWW media, and it still works on the other end.
When you name something, you have power over it. Like the dreidel mnemonic of the title, names help you to remember stuff. You can speak clearly about places and objects instead of just using misunderstood pronouns and long descriptions. And best of all, if you know something’s name, you can use it in casting a spell. (We call them programs.)
So a big part being able to work with virtual worlds, talk about them with other people, and use them in programs is to have a name – a URL that corresponds to each interesting thing about a virtual world.