[Galadriel55]

I suppose that the label isn't meant to be a special symbol that marks the Ring itself, but rather a symbol that marks the power the Ring possesses. Sauron has no need to tag the Ring, but he put a significant amount of power in such a small thing. How do you transfer your power to an object? I don't think there's a yes or no answer to this question; however, I highly doubt that Sauron just said, "Let it be done!", and it was done. In my opinion, he didn't just dump all his power at once into it, but rather etched that verse into the Ring's being. Not into the gold itself, but into its essence. And it was so potent that you could see it come through when you brought the Ring closer to fire. Hence, you do not only see some random inscription, but it tells you something about the nature of the Ring in ways other than words. The fire aspect simply reflects its "place of birth", so to speak. The Elven characters denote the contributors of the art that allowed such a Ring to be made. And lastly, the Black Speech - well, this one's pretty obviously pointing to Sauron and the Ring's will and purpose.

This is what my metaphysical side suggests. This is not based on anything other than my own imagination. I enjoy thinking that one's power could be transferred into objects through art when one puts his heart into it, and that's all there is to this explanation.

It's a curious question, though. I recall from UT the story of Aghan the Druedan who made a living statue of himself. That's also art. And he put so much of himself into the magic replica that when its feet were burned in a fire, Aghan's feet were burned too. If this thought merits a tangent, I will create a separate thread for it as to not kick this one out of its orbit.