"[It] finds its rightful home in the subtlety of a fine and rich analysis, one which is not afraid to pronounce - and sometimes to withhold - judgment where mere affirmation might be found wanting. It allows the writer to link ideas without breaking a train of thought; by contrast, over-simplified communication and bald, efficient discourse whose simplistic style is the best guarantee of being widely understood is naturally wary of [it]."
"It," of course, is the point-virgule, or semicolon. My PG-13 rated (for language; the author is British) source comes with a hat tip to the ever-excellent Marginal Revolution.
Not everyone is so fond of semicolons, though. From the same source, Kurt Vonnegut had this to say about them:
"They are transvestite hermaphrodites, standing for absolutely nothing. All they do is show you've been to college."
For my part, you may have noticed that I very seldom use them, though I often use a comma where a semicolon ought to be.