In fact, online buyers spent $3 billion in March, $650 million more than they did the month before, according to a study released Wednesday by the National Retail Federation and Forrester Research, Cambridge, Mass.

The researchers said online shoppers bought more computers and electronic goods, as well as airline tickets and other travel items, such as car rentals and hotel reservations, while spending less on what are considered the traditional category leaders — software, books, and CDs.

Spending on computers and electronics was up $250 million over the previous month, while appliances showed a six-fold increase, the single biggest growth of the items the panel of consumers said they bought.