eBay Experience Bodes Ill for Amazon.com

Similarly high expectations from eBay helped to sink its stock on Thursday. The company raised its full-year earnings guidance by four cents a share to $1.10. But considering that the company beat its own second-quarter outlook by four pennies a share, it didn't really raise guidance at all. And its updated estimate was still below the pre-call consensus forecast of $1.11 a share in earnings.

Investors seem relatively confident that Amazon, like eBay, will meet second-quarter expectations. But there is considerable concern that, as with eBay, Netflix and Yahoo!, Amazon won't beat expectations or won't raise guidance by a sufficiently high amount. As of June 7, speculators were shorting nearly 11% of Amazon's float, according to Yahoo! Finance.

"You've got to be crazy to be long term in these names," said one fund manager, who requested anonymity and is short both Amazon and eBay. "When you are priced for perfection, any imperfection is what people focus on."

Indeed, current and future earnings aren't the only concern. With so much of the companies' value built on expectations of growth three, four or five years down the line, count on investors and analysts to scrutinize their reports for any troubling news on overseas growth rates, customer-acquisition rates or sales of products in new categories.

E-commerce investors also should be wary of how the broader market has been performing of late. The market has been punishing a slew of stocks, not just Internet ones, after their earnings reports, said Rothbort.

"This is a market right now that is acting in a very irrational way," Rothbort said. "It's not rewarding good performance."

That may be troubling for Amazon, because Wall Street has such high expectations for its upcoming report.