For a lot of people, Amazon Prime Instant Video is a bit of a puzzle. For starters, one-fifth of people who have access to Amazons Netflix-like streaming service, which is an added benefit for those who pay a $79 annual subscription to Prime, the companys loyalty program, dont even use it. Perhaps some Prime members, who likely subscribe for the free two-day shipping benefit, dont know about Prime Instant Video. Amazon, after all, is known as a retailer, not as a streaming powerhouse, and Prime Instant Video was only added three years ago.