The Risks sections are always like that. Any advertisements for stocks must have disclaimers about a wide range of possible risks, and that despite promising historical data you could lose your entire investment. Otherwise they could face expensive lawsuits when future shareholders claim that they were misled and not informed of these risks.

For example from Facebook's S-1: "Growth in use of Facebook through our mobile products, where we do not currently display ads, as a substitute for use on personal computers may negatively affect our revenue and financial results.", "We expect our rates of growth will decline in the future."

Google's S-1: "We expect our growth rates to decline and anticipate downward pressure on our operating margin in the future.", "We are susceptible to index spammers who could harm the integrity of our web search results.", "New technologies could block our ads, which would harm our business."