Originally Answered: Question(s) about business start-up (business license, tax ID, incorporation, etc.)?
My mantra has always been to keep things simple, if possible.
At this point, when you haven't even started the business and whether it will work or not, do you really need to incorporate? You are not going to operate a service business -- e.g. contractor or daycare operator -- where you have a huge chance of getting sued (LLC and corporations allow you to separate personal and business assets).
You can start as a sole proprietorship, which means you just go to your county and register your business and get a DBA. And no, you don't need to register for each one of your website. You can have 1 DBA and operate 10000 websites if you wish. As sole proprietorship you also don't need an EIN or Employer Identification Number
I've met so many enthusiastic business owners who, in all their excitement of starting a business, go all the nine yards -- incorporation, EIN, etc. -- and then after a year has not even started or already closed shop.
You can start as a sole proprietorship first, and once you start seeing that the business is working, then do your incorporation. No need to rush it
Trademark your website name, if not currently used. It's always good sense to protect your name. That's about $300+ with USPTO http://www.uspto.gov -- but you can start even without trademarking your business names and websites.