The holiday season in 2007 will again be a strong one for online holiday shopping, with 84 percent of consumers planning to spend at least as much online as they did during the 2006 season, according to Advertising.com's second annual online holiday shopping study, reports MarketingCharts.

Moreover, this year's buying cycle will be significantly longer than in the past, according to the survey: 50 percent of respondents said they would start shopping for holiday gifts in October or earlier.

In 2006, 44 percent of survey respondents said they would begin holiday shopping after Thanksgiving, while 15 percent said they wouldn't begin shopping until the last two weeks of December.

However, many consumers will be waiting until November and December to make their actual purchases: 77 percent of respondents said they purchase the majority of their holiday gifts in November or December.

Data from the Advertising.com network supports the notion that consumers are making their purchases later, with conversion rates approaching 20 percent during the third week of December, up from around 10 percent a month earlier. The highest conversion day in 2006 was December 15, at 20 percent.

"The holiday season no longer starts in Q4, with consumers beginning their shopping earlier and earlier," said Lynda Clarizio, president of Advertising.com.

"To fully capitalize on this lengthy shopping season, advertisers should look to leverage marketing tactics for each stage of the consumer purchase cycle - such as online video to build awareness, search marketing to drive traffic, and behavioral retargeting and late-season incentives to close conversions."

MarketingCharts provides additional findings from the Advertising.com study.