if you were a partner (not a shareholder) in GLBSE then you are liable for the actions of GLBSE, which you allowed Nefario to run. If GLBSE was registered as a corporation or a limited liability company, then you would only be liable for what you put into GLBSE. If you just opened a general partnership, well then you are fucked.
This much has been established earlier in the thread.
I do wonder what legal recourse you have (if any?) if you are lied to when you make the investment? If someone tells you they are a company, (company = incorporated) and you invest, do you still have this liability?
I've bought a lot of stocks on etrade and I don't think I've ever dug up their actual incorporation paperwork.
I know, it just pisses me off that anyone could open a business and not know the risks involved.