Call it the Holiday Retailing Death Match: Team Black Friday versus Team Cyber Monday. Brick-and-mortar versus e-commerce sales. Physical stores pitted against the power of the internet.

During the just-wrapped Christmas shopping season, e-tailers were more aggressive than ever before in offering discounts and other kinds of come-ons to customers ordering over the internet. But they paid a high price for that strategy.

Import volume at the nation's major retail container ports is expected to grow 1.8 percent in December over the same month last year, and the year should end with an increase of 2.3 percent over 2012, according to the monthly Global Port Tracker report released by the National Retail Federation and Hackett Associates.

As retailers rush to get their online holiday offers out early, many are missing out on a major selling tool that drives web shoppers to buy: free shipping.