There has been real concern about this year's e-commerce numbers. comScore has online spending up about 18%. The data for the period from November 1 through December 14 show sales of $22.67 billion.

But, these numbers are down from a growth rate of 26% for the same period last year. Part of that may be due to big percentages being harder to hit as the base grows. That explanation may not be acceptable to Wall Street. Online revenue is still only about 5% of total retail sales. A drop-off in the numbers must have some other explanation.

It turns out that there is reason, and it is an unpleasant one. comScore's data show that people in households with incomes under $50,000 have only increased their spending 10% so far this holiday season. Shoppers in households with incomes over $100,000 are spending 28% more.

What is evident is that people with modest incomes are feeling pinched. It's no wonder with fuel prices high and home prices low. These essentials usually make up a larger portion of the budgets of those who are not in the affluent tiers of the population.

Who gets hurt by the numbers? Discount retailers which cater to the middle and lower classes such as Wal-Mart.com (NYSE: WMT).

Douglas A. McIntyre is an editor at 247wallst.com.