ChannelAdvisor: 'Cyber Sunday' Sales Up 18%

Online retail sales on Sunday were up 18 percent from a year earlier but amounted to the slowest growth pace so far in the intense holiday shopping period that started Thursday.

Amazon.com, Inc.'s (NASDAQ: AMZN) sales Sunday grew 23.8 percent Sunday, the fastest pace of six "channels" tracked by ChannelAdvisor.

The company is calling the period from Thanksgiving to December 1 the "Cyber Five Days," in a variation on the term Cyber Monday, coined in 2006 by the National Retail Federation.

Amazon's growth pace slowed from 45.9 percent Saturday, according to ChannelAdvisor.

Trailing Amazon's sales growth, eBay Inc (NASDAQ: EBAY) came in second on ChannelAdvisor's list of companies' online sales growth Sunday, with an estimated increase of 16.3 percent, down from 14.9 percent Saturday.

Google Inc's (NASDAQ: GOOGL) shopping channel grew 15.8 percent, compared with 19.7 percent Sunday.

Across the outlets tracked by ChannelAdvisor, about 71 percent of orders were made on computers while 18 percent were via tablets and 11 percent on smartphones.