If  Facebook (FB) told you to jump off a cliff, would you do it? You just might. And it’s this blind confidence and leap of faith that investors are looking to make this week as Facebook goes public. With current financial projections for the social media giant riding on future advertising and mobile growth, it’s a little daunting to note that the core numbers in play are all being made in a haze. Let’s start with a quick fact that is not too hazy – Facebook relies on ad sales for 85% of its $3.71 billion in annual revenue.

To get a better feel for the overall social advertising world we are playing with, we can look at some recent results. As of October 2011, social networking websites received just 14.8% of all estimated display ad spending, according to comScore. There is a major opportunity for growth here, which is why the “Big F” likes to forecast the future with such gusto. There is no doubt that the social advertising marketplace is going to continue to gain more traction, but how far and how fast this traction occurs is up in the air.

While 84% of North American execs in a new eMarketer study believe social-media campaigns increased marketing effectiveness and sales efforts, over 50% believe the lack of a standardized metric that can measure a return on investment remains a major obstacle. Facebook reported a 37% year-over-year leap in ad revenue to $872 million in the first quarter, but a 7.5% decline sequentially due to “seasonal trends” and shifting user growth.To continue reading, click here.