* Founding artist Gisele Lagace came up with the original concept for the comic, basing the title characters and their rivalry on two conflicting sides of her own personality as a teenager. She also designed the look and basic traits of the initial seven characters: Penny, Aggie, Nick, Lynda, Rob, and the title characters' respective pets, Charles the cat and Finister the rat. The pets were initially meant to have larger roles.
* The title characters' names are based on the game of marbles. Pennies are often used as stakes in the game, and "aggie" is a synonym for "marble."
* Stan's and Jack's names, as well as their general personalities, are inspired by StanLee and JackKirby.
* The series, while appearing online from the beginning was, for over a year, pitched to syndicates as a [[NewspaperComics newspaper comic]]. The Washington Post Writers' Group came close to picking it up; however, it lost out to another strip.
* The first few storylines were also published as a limited-run full-colour ComicBook from Alias Enterprises.
* Charlotte's screen name refers to Literature/TheBible verse "An evil man seeks only rebellion: therefore a cruel messenger shall be sent against him."
** The original concept for the strip included a broader, SitCom-like focus on the title characters' families. To that end, Penny was initially meant to have a bratty, eight-year-old brother, Matt ([[http://www.pennyandaggie.com/index.php?p=1119 concept sketch here]]), who would have served as another foil for Penny. However, Campbell soon realized he was writing Penny as if she were an only child, and both he and LagacÚ had by then largely moved toward a focus on the teenage leads.
** Other story ideas which Campbell considered, but in the end rejected, included Karen [[TeenPregnancy getting pregnant]], a [[GreenEyedMonster jealous]] Rich beating up Duane over Penny, and Aggie losing her virginity to a fellow Obama campaign volunteer on the evening of the 2008 presidential election.