Some markets are tightly constrained by legislation; very few are completely unregulated.
You need fully to understand the potential impact of regulation, legal frameworks and standards applicable to your target market on the design and specification of your offer. This is is clearly critical in areas like food safety, health, education and electrical products and services but will be relevant across a very wide range of other sectors too.
Standards and changing legislation can often be a stimulus for innovation: tighter emissions standards, for example, are driving significant developments in the automotive industry.
You should also consider cultural, ethical and social standards that, although not enforced by law, might influence your customers' decisions. Recycling, animal welfare, working conditions in developing countries are the kind of factors which you may need to take into account.
Components of Rules:
Freedom to Operate
Are their any hurdles that mean that your product cannot be sold to the market. This includes Intellectual Property barriers e.g. Patent protection, copyright of a product name.
What governs the provision of products and services in the markets you've identified? Have you considered all the requirements that will have an impact on the design of your offer?
What are the product or service standards that you must comply with? These often have BSI numbers, or EN numbers if you're working in the EU's regulatory framework.