I believe creativity exists in everyone, the only difference is how the individual puts it to use. It could be seen through talking, cooking, singing, sketching, driving, fashion, and to even arranging books on a shelve.
Being in the Advertising certainly needs more than just one application of creativity. It has to cater to all who possess the talents listed above, and they, need to be able to connect to the ads that the advertisers have come up with. Without a doubt, each individuals taste varies, and therefore, I feel advertisers (who are successful in their campaigns of course) are the ultimate architects of Creativity!
Interesting it is to look at creativity in the same context as energy: can't be created nor destroyed, only manipulated :)