Hmm..Did you do a work of art in Poser? Did you get paid for it? If the answers to 1 and 2 are 'yes', then congratulations! you have a Professional package!.;)
To be honest, it's mainly attitude. I'm sure some people could do 'professional' work with MS-Paint..;) For some of those 'other' web sites..the only thing that would convince them would be if the name 'Poser' was retired, and a commensurate multi-hundred dollar price tag attached..;)

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)