Should users control their online identity? It is a known fact that users like to use a pseudonym in the online social world (rather than identity themselves).
With the advent of Web 2.0, the paradigm has shifted towards the user. It is a push rather than a pull model as far as the web is concerned.
It is appropriate to say that the user has full rights over his identity. The 7 laws of Identity by Kim Cameron may be the first place to look for justification.
Here is a short write up on User Centric Identity that I found online:
Primer on User-centric Identity Access Management
Additionally, "Internet Scale Identity, Collaboration, and Higher Education"