Amazon may have surprised Wall Street by how much sales went up in the fourth quarter of last year ($29.3 billion, with a profit of $214 million), but for customers its Prime service is the big deal. Founder and CEO Jeff Bezos said Prime membership in the US grew by 50 percent last year, despite a price hike. That growth probably explains (and helps justify) the expanding number of services it's tacked on to what was originally just an offer of free / cheap shipping. According to Bezos, Amazon plowed $1.3 billion into Prime Instant Video alone in 2014, snapping up exclusives, content from HBO and creating award winning programming like Transparent.

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