Since the introduction of the Kindle in late 2007, the online retail giant has marketed the device almost without interruption on its home page, which drew 65 million unique visitors in April. That audience, combined with Amazon's fervent Kindle advertising, generated more than 60 million ad impressions in May and click-through rates averaging 1.6% this year, with a high of 3.4% for the week ending Feb. 14, according to the analysis by Compete.

Typical banner ads average click-through rates of well under 1%.

"These efforts, coupled with largely positive reviews, have helped drive high consumer demand for Kindle. Kindle interest has grown steadily over the past 18 months, with recent jumps attributable to the 2nd generation launch in February and the announcement of the larger-format DX reader last month," wrote analyst Matt Pace, in a post on the Compete blog Monday.

On Monday, Amazon announced that the new DX model, designed for reading newspapers and magazines, would ship June 10. Powered by the Kindle's popularity, a new In-Stat forecasts that the e-book market will grow from $323 million in 2008 to nearly $9 billion in 2013.

Were the prominent display ads on the home page not helping to stoke consumer interest, Pace concludes that Amazon would have replaced them with something else. But how do home page ads stack up against other ad formats in driving Kindle referrals?

The Compete study finds that ads drove nearly 45% of all visits to the Kindle product pages, while another 26% came from other places within Amazon such as banner ad text links, searches within the site and category navigation. Meanwhile, search engines such as Google and Amazon email campaigns accounted for 6% and 5% of traffic, respectively.

Looking at post-click results, however, the firm found that search drove the highest levels of use engagement and purchase intent. Consumers referred through search engines averaged over 5 minutes learning about Kindle on product pages, compared to only 3.5 minutes for shoppers coming through the home page links. That's not usual, given that searchers are looking for a product to begin with rather than responding to a marketing message.

A slightly higher proportion of consumers coming from search engines (4.3%) added a Kindle to their shopping cart than those from the Amazon home page or other Amazon pages. "Email, on the other hand, fared poorly with consumers spending considerably less time viewing the product and relatively far fewer demonstrating immediate purchase intent," according to Compete. In short, don't expect Amazon to turn the page on those Kindle ads anytime soon.

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