Chris Dixon has a great blog post on types of risks:
– Financing risk: You can’t raise money at various stages because you haven’t hitaccretive milestones or your space isn’t appealing to investors.
– Product risk: You can’t translate your concept into a working and compelling product.
– Technology risk: You can’t build a good enough or, if necessary, breakthrough technology.
– Business development risk: You can’t get deals with other companies that you depend on to build or distribute your product.
– Market risk: Customers or users won’t want your product.
– Timing risk: You are too early or too late to the market.
– Margin risk: You build something people want but that you can’t defend, and therefore competitors will squeeze your margins.