Several reporters have pointed to a big risk that they discovered in Facebook's SEC filing: mobile.

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 had more than 425 million MAUs who used Facebook mobile products in December 2011. We anticipate that the rate of growth in mobile users will continue to exceed the growth rate of our overall MAUs for the foreseeable future, in part due to our focus on developing mobile products to encourage mobile usage of Facebook.

How exactly is this a risk? Well, they found it in the Risk Factors section of the S-1 filing! Therefore it must be a risk!

The "Risks" section is standard boilerplate, it is where management puts everything that could go wrong, it's a kitchen sink where it includes things like, Mark Zuckerberg's death, what if he were to leave the company, what if we mess up on this and that.

A little bit of thought would quickly show that mobile is far from a serious risk to Facebook's future but a massive, untapped gold mine. With 425 million active users in December alone, it's an incredible revenue opportunity that isn't being monetized yet. This is the cherry on the cake for the Facebook IPO.

Mobile advertising is the fastest sector of online advertising, it's exploding: From $1.5 billion in 2010 to $15 billion by 2015 and some estimates put the total value much higher. Companies are paying huge premiums for mobile ads.

Yet leading news sites are warning of a massive risk to Facebook!

VentureBeat reports: In light of Facebook's huge mobile risk, a "Facebook phone" looks like a smart solution

Here is GigaOM: Facebook just revealed its Kryptonite: mobile

Techcrunch: Facebook's Risk Factors: Mobile, Gov, Slowed Growth, Google+

AllThingsD: Mobile Highlighted as Key Risk Factor