It is sometimes thought that because a business is not bricks-and-mortar, but merely a guy sitting at home clicking a mouse, that it isn't "doing business." This point of view would not get much traction in court. A person is "doing business" by conducting operations of any regular and substantial kind that contribute to a venture intended to make a profit.
Delaware is a suitable state for incorporation of a business that is (a) listed on an exchange, and/or (b) conducts business in all, or many, states. If neither of these factors is present, it's hard to find any reason to domicile a business entity there.
California's business francise taxes may be a reason not to incorporate or form an LLC, but if you do form one, and it will conduct any kind of business here (like receive payments, make policy, hold meetings, make decisions, keep the records) you are going to be paying those taxes anyway, plus taxes to Delaware or wherever. Perhaps even more a nuisance, you'll be keeping records and filing reports in all states where you do business, or are domiciled.