Despite a world of e-commerce choices and possibilities, when it comes to where Americans shop online, there's really only one answer. Amazon. For the second year in a row, more Americans will shop online for all or most of their holiday gifts, more than ever before in the 12-year history of CNBC's All-America Economic Survey. Forty-five percent said e-commerce is the top place they have shopped or plan to shop this season. While it's the second straight year that online is the top shopping destination, it's 5 percentage points above last year and more than twice as popular as it was a decade ago.

But the real eye-opener is just how much Amazon dominates. Seventy-six percent of Americans shopping online this holiday season expect to do most of that shopping on Amazon. No other retailer or website is even close to the king of the online jungle. "As much choice or selection as the internet provides, it's just an amazing set of data to see all that concentrated in one online retailer," said Micah Roberts, a partner at research firm Public Opinion Strategies. "It really underscores the dominance in that space." Walmart comes in second, but far behind, with only 8 percent of Americans who shop online searching or checking prices there, with other retailers clumped close behind the discounter.

For Americans who shop online, 65 percent search on Amazon always or most of the time, up sharply each of the last 2 years. Online conversion, or the rate of getting consumers who browse to follow through with a purchase, is notoriously small. Most estimates put the average rate of overall online conversion at around just 3 percent. But Amazon has broken the mold on that one too, according to the results of CNBC's survey, with 57 percent of Amazon searchers buying on the site always or most of the time. When asked what's most important when it comes to online shopping, 43 percent say free shipping. Of course, in order to get free shipping from Amazon, you have to spend at least $25 per order or pay $99 a year for a Prime Membership. The ability to compare prices ranks second, at 26 percent, followed by the availability of product information at 18 percent. But while price comparison is second in terms of importance, the digital divide within incomes persists when it comes to online shopping. Of Americans who do a lot or a fair amount of shopping online, 20 percent have incomes of $30,000 or less, while 62 percent make $100,000 or more.