The logical course that this differentiation follows would, I believe, flow down to the level of the individual. Enterprises may very well be - and are spoken of most highly when they are - individual enterprises.
Although this was probably not in the minds of those who developed the neo-liberal governmentality, the idea of differentiation at the level of the individual matches up quite well with an idea we can see in Lacan's psychoanalytic theory. This idea is that of the "decentered subject." In The Plague of Fantasies, Slavoj Zizek writes that "'Decentrement' thus first designates . . . the undecidability as to where my true point is, in my 'real' self or in my external mask . . ." This ambiguity, then, allows for the very differentiation within the individual that meshes so well with the neo-liberal project. It is precisely because we can slide between identifications - because, as Zizek writes, "the very process of shifting among multiple identifications presupposes a kind of empty band which makes the leap from one identity to another possible . . ." - that we are able to project the identification which makes us most "valuable" in the moment.
This shifting from one identity to another can be seen fairly clearly online. Subjects have multiple email accounts, multiple accounts on social networking sites (Facebook, Myspace, Twitter, Friendster), and, subsequently, slightly different identities for each. What we see, then, is a diffraction of subjectivity at an individual level. Since it is impossible - or nearly, at any rate - to pinpoint exactly who our "real" selves are, it becomes easier (and the virtual world online facilitates this) to assume different masks in different situations.
To bring it back to Foucault, he posits that neo-liberal govermentality attempts - through constant intervention on the "conditions" of society - to bring every facet of life under the regulation of the market. My "added value" to his idea is this: we assume different identities, different masks, in different markets. With the proliferation of these markets into more facets of life, we must create and take on more masks - and it is the void of our subjectivity that allows this governmentality to proceed as it does.
-the ambassador