Maria Bustillos on romance novels: 

So there’s no sniffy condescension or po-mo posturing in a romance novel; they’re the least stuck-up books in the world. Everybody knows that they are written and read just for kicks, and that gives the author an enviable freedom within which she may permit her imagination to run riot. And does it ever. These writers hve no authorial brakes at all, and their irrepressibility is enchanting all by itself. What other kind of author is free to name her hero Sin Watermount or Don Julio Valdares, Tarquin Roscuro or Duc Breul de Polain et Bouvais? There is generally a wild, far-flung and exotic locale: Queensland, the Western Cape of South Africa, the Scottish Highlands. There are impossible situations, natural disasters, a whole pantheon of dei ex machinis, drama galore. And there is, always, falling in love.

Although romance novels as a genera are easy to ignore, they are a deeply ingrained part of the culture. 

It doesn’t matter whether you call this “serious” literature or not, really, though it seems to me that when millions and millions of people are involved in the same reading, it is very serious indeed.