Pepsi One is essentially an alternative to
Diet Pepsi marketed towards men.
Marketing types found that 'diet' drinks are considered by many to be an
effeminate choice. Pepsi One is positioned as a
one-calorie alternative that men can drink under the
guise that it tastes better, rather than admitting that they are dieting. The advertising campaign features
Tom Green being anything but effeminate.
It's the domestic equivalent to Pepsi Max , which is found in many countries overseas. They serve the same purpose, though the formula used to mix sodas varies from country to country. I've been told by Irish travelers that all of our sodas in the US taste like chlorine. Elsewhere, sodas may be mixed to taste extremely sweet. Pepsi Max is positioned as an 'extreme' (can you handle it?) soda, much like Mountain Dew's positioning here in the US, backlashing from effeminate to point more at macho.