Investors are a little nervous about Twitter's IPO, because it was revealed that the micro-blogging platform only owns less than 10 patents. Compared to Facebook's 774 patents Twitter doesn't really own the rights to much of the technology is runs on. Twitters small number of patents is based on the companies philosophy of letting engineers and designers own their inventions. This is a great policy for the works at the company but investors see this as a window for other companies to draw those same developers and engineers away from Twitter so they can bring that technology to their companies. Its important for a company like twitter to own the patents because it makes it more valuable to own technological breakthrough instead of letting a sole person own them.