Tracker finds Cyber Monday sales up 30% over 2011

Online holiday shoppers spent 30 percent more on Cyber Monday than they did in 2011, as more consumers used smartphones and tablets to make purchases.

More than 18 percent of shoppers used a mobile device to access a retailer's website, an increase of 70 percent over 2011, according to a report Tuesday from International Business Machines Corp. Mobile sales almost doubled, making up 13 percent of total Web-based purchases.

Internet sales on so-called Cyber Monday, when many retailers discount items online as Americans return to work after the Thanksgiving weekend, were 36 percent greater than on Black Friday, the traditional start of the holiday shopping season, IBM said. Apple Inc.'s iPad and iPhone were the top two devices used for online purchases, accounting for about 14 percent of the total Monday.

"Cyber Monday was not only the pinnacle of the Thanksgiving shopping weekend but when the cash register closed it officially became the biggest online shopping day ever," IBM Smarter Commerce strategy director Jay Henderson said in a statement.

Online retailers are poised for a record $43.4 billion holiday sales season as shoppers increasingly rely on social networks and mobile devices to find and buy merchandise, according to market researcher comScore Inc.