Having been there during the first season of Smallville, I can tell you that a lot of people came out of Buffy fandom, where initials were used to indicate pairings (B/A = Buffy/Angel, X/W = Xander/Willow, etc). Except everybody in Smallville has the first initial L or C. Lex, Lionel, Lana, Clark, Chloe. With initials leading to ultimate confusion, Clex appeared, somehow. And there was also Chlark, and Clana, and Chlana. I prefer to spell everything out, myself, but at least that gets into the origins of portmanteaux pairings in Smallville a little bit.