It's not uncommon to meet would-be software entrepreneurs with stars in their eyes. This number crunching from Aileen Lee does a good job of showing just how difficult serious software success is. The focus is on the so-called "Unicorn Club", US-based software companies started since 2003 and valued at over $1 billion by public or private market investors.
The reality check: only 0.07% of venture-backed consumer and enterprise software startups make it this far.
Takeaway: it’s really hard, and highly unlikely, to build or invest in a billion dollar company. The tech news may make it seem like there’s a winner being born every minute — but the reality is, the odds are somewhere between catching a foul ball at an MLB game and being struck by lightning in one’s lifetime. Or, more than 100x harder than getting into Stanford.
http://techcrunch.com/2013/11/02/welcome-to-the-unicorn-club/