Cyber Monday is the first Monday after the Thanksgiving holiday and is famous for the abundance of promotions offered by online merchants, and is expected to be the largest day of online shopping in the United States this year.

Rob Jarve, vice president and general manager of retail at Salesforce, said the high rate of online traffic on Black Friday, the day after Thanksgiving, showed how much effort and time it takes shoppers to choose the least expensive and most valuable merchandise.

Salesforce tracks the data flowing through its e-commerce service known as Commerce Cloud.

Garve added that U.S. retailers "raised the discounts" to nearly 30 percent on average on Black Friday.

The company says total shopper purchases on Black Friday were $16.4 billion in the United States and $70.9 billion globally.

The company expects discounts on online Monday to reach 30 percent, noting that consumers may not find the products on offer again if they decide to wait for higher discounts.

Adobe Analytics expects shoppers to spend a record $12 billion on Monday, a 5.4 percent increase from a year ago.

Vivek Pandya, senior analyst at Adobe Digital Insights, said retailers were expected to offer price reductions of up to an average of 30 percent on electronics and 19 percent on furniture on Monday.

Pandya said shoppers on "Cyber Monday" could spend $6 billion between 11 p.m. and <> p.m. EDT "because they'll be worried about weak discounts afterwards."

Mastercard, which measures retail sales across all forms of payment, said e-commerce sales rose 8.5 percent on Black Friday, while in-store sales rose one percent.