Over time, Delaware has developed as the incorporation capital of America. It started off having very business-friendly tax and liability laws, so businesses started to incorporate there, even if the business actually does no business there. Delaware realized this was good for the state coffers if all the big businesses incorporated and paid taxes there, so the corporate laws remained very business-friendly and the courts followed suit. Now, if you want to do legal work for a company that is incorporated in Delaware, it helps to be admitted to the Delaware bar so that you can actually sign the documents that you prepare. It's not a must, but it helps.