I see it as an art, and I wouldn't say art is meaningless. Perhaps you want to check out https://www.facebook.com/tagxedo to see some more examples. It's much more than a blob of tags arranged in some random order to "help" navigation (that might be a bit cliche).

Some of my favorites:

http://daily.tagxedo.com/may-20-linkedin-rockets-skyward-in-...

http://daily.tagxedo.com/may-16-space-shuttle-endeavour-blas...

http://daily.tagxedo.com/march-23-faster-much-improved-firef...