Cyber Monday Might Be The Biggest Online Shopping Day in U.S. History Break out your credit or debit card and become a part of history. Cyber Monday is expected to be the biggest online shopping day ever. Forecasters predict $7.8 billion in sales. That would be up 17 percent from last year. The huge shopping number comes even though the Thanksgiving shopping period has spread out from just Black Friday. There have been doorbusters and early deals on many websites since last Monday. Are you planning to do a bulk of your holiday shopping online this year? What have you already purchased on Cyber Monday?