Online shopping revenue is estimated to grow by 25 percent this holiday season, with the most active shopping day on the Web — Black Monday, if you will, to the traditional retail world’s so-called Black Friday — now right around the corner.

Consumers, it has been estimated, will spend more than $15 billion on the Internet for gifts this holiday, according to comScore Networks. That’s up between 23 and 26 percent from the comparable November-December period last year.

Just as it does offline, holiday shopping activity kicks off around Thanksgiving.

But unlike the offline world, where Black Friday, the day after Thanksgiving, is one of the most active shopping days, the Monday following the feast marks the day when the action really gets going on the Web.

Last year, more than $300 million was spent on the Monday after Thanksgiving. The reason consumers spend so heavily on that Monday, according to comScore, is that they’ve “returned to the workplace — long a favorite location from which to shop online.”

From the start of the year through Nov. 14, online retail sales have risen 25 percent to $42.9 billion. The fourth quarter is estimated to ring in about $20.1 billion to $21.1 billion in online sales.

The holiday season will account for nearly three-quarters of fourth-quarter virtual-cash-register sales on the Web, according to estimates.

The head of Yahoo ‘s shopping operations, Rob Solomon, said online shopping this year is expected to peak Dec. 6. In an interview with

Two services Yahoo Shopping has launched this year are “attribute” search and “safe products,” said Solomon.