Having exploded from nothing, the global smartphone industry today represents one of the fastest-growing and most important sectors in all of technology, and this week will bring one of the most important product launches in all of 2013. This Thursday, tech giant Samsung will introduce the next generation of its flagship Galaxy S line of phones: the Galaxy S IV. The launch has major implications for smartphone sales for the rest of the year. We break down what investors should expect from this important devices later this week.