Identity is seen as fluid and performative, composed by almost randomly chosen global impulses. The actual act of shopping, chosing clothes according to who you want to be has a metaphorical equivalent where we are thought to choose traditions, values, rites, food and ideas as easily as T-shirts.
Identity is performatively constituted by the very 'expressions' that are said to be its results.Judith Butler (more on her...)
While drawing attention to the intricate interactions between one's action and "essential idea of self" (the traditional non-performative notion of "identity") this model seems to me to seriously under-estimate the complexities of traditions. Traditions do not come in shopping-bag sized chunks. From classical music to the tea ceremony, traditions are rich expressions of creativity and for many of them it takes the best part of a lifetime to really master and understand them. If we are led to assume that we can "shop" among traditions and return the unwanted goods when we make the next bargain, the pieces of traditions left in our mental shopping bags will be dumbed-down, superficial versions.
This is not meant to deny that people can, do and will seek inspiration in other traditions. It is merely a warning against the happily simplistic assumptions that some academics make about the blessings of "identity shopping".