To reply to a few of your points sol. The difference between hobby and job would mainly be the amount of income, whereby once you reach the threshold and have to start paying taxes for it. PPCA is very much a grey area, but tieing in with your next point, any music/video/games you purchase are done so under a private use which restricts public broadcasting of the content, eg having your friends over to have a movie night is technically illegal. It all comes down to enforcement which is pretty much non existent. Insurance and PPCA may be required for some venues/events which is important to keep in mind if you have any inclination to go corporate/high end stuff. With flyers and advertising it will depend if you are like a moby disco type service you may want some listings on yellow pages etc. Business name is free to register, and might help later on to avoid confusion with a similarly named company. Really though majority of this stuff is unnecessary for majority of people on here unless you are using it to provide all your income, in which it would be a smart idea to cover all aspects legally.