This is really just a media question, about psuedo celebrities, journalists, maybe sales, et al. For by far the majority of nerds and geeks a non-issue.
So something that needs to be sorted out contractually between the identity, their agent, lawyers and the company to whom that public identity (often just a created faÃade which has very little to do with who the person really is) was contracted.
Such it is much like a person creating an anime character, and the person, the company and what ever public relations services are used to created an identity for that character to promote what ever content and advertising that is produced in that characters identity.
So in the modern internet age who owns that 'anime' character, that marketing illusion, the person in whose name it was created, their agent, the company that contracted them, the public relations firms that worked to bring them to life (well zomboid existence, who is the zomboid those that follow it or the object they follow).
Well, as it all revolves around bullshit, let the bullshit lawyers, deal with the bullshit contracts, deal with the bullshit public relations agencies. When it comes to bullshit, there are no solutions except maybe dung bettles http://en.wikipedia.org/wiki/Dung_beetle ;D. Don't know how that helps people who live in the world of PR=B$ (lies for profit) but then again I don't think anything ever really will.