The biggest online shopping day of the year is almost here, but no one can agree on exactly when that day will arrive.

Coremetrics has released a new report claiming that the second Monday after Thanksgiving, or "eDay," is the biggest online shopping day of the year, according to eMarketer. The report attempts to dispel the thinking that "Cyber Monday," or the Monday after Thanksgiving, is the biggest online shopping day of the year. Coremetrics also predicts that sales on eDay will be 19 percent higher than on Cyber Monday - and that holiday online sales this year will grow 16 percent from last year.

In contrast to Coremetrics' findings, Marketing Experiments Journal found that the two biggest online shopping days from 2002 through 2004 were the Saturday before Christmas and the Friday after Thanksgiving.

But a study from Shop.com claims that shoppers' holiday buying habits are changing, with more shoppers spacing out their holiday shopping throughout the year instead of waiting until the last minute. The study surveyed 2,400 U.S. online shoppers, with almost 44 percent saying it is never too early to start shopping. Also, 23 percent said they were constantly on the lookout for good holiday deals. Only 21 percent said that they look forward to the holiday shopping season.