It’s strange — in a culture supposedly so enthralled by youth — that we seem to prefer our vocabulary, like our whiskey, well -aged. We never like to say “words” when we can say “verbiage” (even though that changes the meaning to something far more disdainful than most people intend).
We don’t lay sewer lines, we prefer sewerage (even though that confuses people who think you mean sewage, the rank stuff that runs through the sewers). People who sell newspaper advertising measure their ads not by the number of lines of type they occupy, but by their lineage (even though an outsider might confuse this with some question of genealogy).
The popularity of “signage,” like that of these other coinages, seems to lend some kind of dignity or expansiveness to the meaning of the ordinary word. The fancier term seems to announce, “we don’t just lay sewer pipes or paint signs — there’s a big, exquisite, sophisticated system to it” — which is true, I suppose, though often irrelevant. Nine times out of ten, when you see “signage,” it just means signs. The tenth time, it probably means “a system of coordinated signs” — which am.