Some 122 million Americans are expected to shop online on Cyber Monday, estimates. 

Online sales increased 17.4 percent on Thanksgiving and 20.7 percent on Black Friday over 2011 figures, reports IBM Smarter Commerce, a unit of IBM that analyzes transactions from 500 U.S. retailers, according to Reuters.

"The online players are definitely participating more on Thanksgiving and Black Friday, so Cyber Monday is being shared with other holidays now," Scot Wingo, chief executive of ChannelAdvisor, told Reuters.

Mercent, which helps merchants sell on websites including Amazon, eBay and Google's online shopping program, estimates that client sales rose 23 percent over 2011 Black Friday and 32 percent year-over-year on Thanksgiving.

Online websites are awash with tips on how to win the best bargains on holiday gift lists. AARP has released an advisory against online scamsters warning buyers to protect themselves from online theft and offers tips for safe shopping.

The term Cyber Monday was coined by in 2005.

While retailers look forward to more online revenue this season, some may face higher costs in shipping packages to shoppers.