I noticed an interesting use of underlining at the gas pump today. I learned, when studying typography, that underlining is mostly a relic of the typewriter, which was incapable of emphasizing text with italic or bold typefaces, and that other means of emphasis are more aesthetically pleasing.
One problem with underlining words as a way of underscoring their importance is that the underlines interfere with the descenders– those “tails” of letters that descend below the baseline as in the lowercase letters g, j, p, q, and y. I once read that a proper underline breaks at the descenders to allow them to descend without interference.
I am happy to report that the typesetter of this sign knew well enough to underscore only the “round” of the word “ground” and let the descender of the lowercase g hang down without the interference of the underline.
You just never know where you’ll see an example of proficient typography! Er… typography! Yeah, that’s better.
Daniel Greene 
Comments welcome