Surely if putting word about some event on a website counts as a commercial activity, which can be prohibited within a neighbourhood, that would include selling something on e-bay.

Presumably a home recording studio would be illegal too. What about writing a book you hope to get published? What about reading a book you hope might help you get a job?

Leadbelly put it rather well:

"Home of the Brave,
Land of the Free,
I don't want to get mistreated by no Bourgeoisie"