As part of upgrading Amazon from neutral to buy, Piper Jaffray analysts Gene Munster and Nicholas Gallus entered the Kindle guessing game, estimating that the e-book reader could account for 2% of Amazon's sales this year and 4% in 2010. In addition to revenue from the Kindle, Piper raised its outlook for Amazon because it said their survey last week of 300 online shoppers shows that satisfaction remains high with Amazon, at 81%.