A new batch of data on ecommerce spending contains some potentially bad news for Amazon.com and other online retailers.

Internet measurement firm comScore reports that U.S. online spending grew by just 1 percent in October from the same month a year ago -- the lowest monthly growth rate since comScore began tracking ecommerce in 2001.

Those are grim figures as Amazon and other online retailers gear up for the holiday season, normally one of the biggest sales periods of the year.

Much of the shrinkage in October was due to curtailed spending by lower and middle-income consumers, the data show. Households earning less than $50,000 per year actually showed spending declines from a year ago.

ComScore chairman Gian Fulgoni had this assessment:

"While rising prices remained consumers' biggest concern in October, it's clear that the increase in the country's unemployment rate along with the shock of the financial market meltdown have had a negative impact on the psyche of the American consumer, and the effects were clearly felt in the online retail sector," Fulgoni said.

He added: "October represented the softest single-month of online retail growth on record, and we can only hope that the recent sharp drop in oil prices will cause a continued easing of inflation and a strengthening in consumer spending as enter the critical holiday shopping season."

Amazon has rolled out a bunch of new innovations ahead of this year's holiday shopping season, including Daily Deal Text Alerts and Universal Wish Lists that let people add products from any website to their Amazon Wish List.

Still, some analysts are sounding the alarm about ecommerce in the current economy.

Mark Mahaney of Citigroup recently downgraded Amazon to a hold rating, citing slowing online sales at other e-tailers, including online jewelry store Blue Nile.