thechef714 - Which country would you be from? I can't speak for experience outside the US.
I can tell you from my experience that in the United States you do not need to advertise anything for compliance for getting a business license / reseller certificate. And yes, irrespective of whether you are selling online or offline, it is advisable to get a sales tax # / reseller license from the Govt as most wholesalers would not sell goods to you without this. We are bound to collect the license and you need to fill an exemption certificate if you wish to buy from a wholesaler from the same state you have your business in. Else, you would end up paying sales tax on the transaction.
Hope this helps. Do feel free to reach out to me with any questions you may have. Happy to help!