Coulomb's law in vector form emphasizes the importance of direction, especially when dealing with opposite charges, as the force vector can align with or oppose the position vector. The discussion highlights that expressing direction is simplified when using absolute values. Charge density can indeed be negative, which facilitates direction representation in calculations. The conversation also touches on the challenges of using LaTeX for formulas in forum posts, suggesting resources for better understanding. Overall, the thread provides insights into the nuances of vector representation in electrostatics.