The centerpiece of Ford’s new Mustang campaign has been the online Mustang customizer, which lets pony car enthusiasts build their own virtual Mustangs using Ford Racing performance parts. It’s a great tool that let’s us lust over our dream cars, while giving Ford insight into the cars and parts people seem to most enjoy.

Since going live in the fall, the Mustang customizer has been over 4 million (and counting) digital Mustangs made, reports egmCarTech.

The Mustang customizer is part of a larger Ford plan to market its vehicles via social media services like Twitter and Facebook, as opposed to traditional media outlets like television and print ads. This whole social media campaign kicked off in 2010 with the all-new Ford Fiesta. Now Ford is applying techniques learned from Fiesta and other campaigns into marketing its more traditional vehicles, like the Mustang and F-150.

Indeed, even in the Mustang’s more “traditional” television spot, Ford highlights that immense customization that the pony car offers. The whole “Inner Mustang” campaign shows how there is a Mustang that appeals to many different types of individuals across genders and age groups. With Mustang sales experiencing a major uptick in February, it seems like Ford’s social media campaign might be on to something.