More than $26 billion was spent online during the first 51 days of the 2007 holiday season (Nov. 1-Dec. 21), representing a 19 percent increase compared with the same period last year, according to ComScore Inc.

Monday, Dec. 10, or "Green Monday," was the heaviest individual spending day of the season with $881 million in sales. "Cyber Monday" (Monday, Nov. 26), which represents the first major spike in online spending activity during the season, ranked as the ninth heaviest day with $733 million in sales.

ComScore forecasts that online retail spending will reach $29.5 billion for the 2007 holiday season, up 20 percent from $24.6 billion in sales last year.

ComScore Inc. measures the digital world based on a global cross-section of more than 2 million consumers who have given the company permission to confidentially capture their browsing and transaction behavior, including online and offline purchasing. ComScore panelists also participate in survey research that captures and integrates their attitudes and intentions.