A weak economy will slow the growth of online shopping this holiday season, according to a new report from Forrester Research.

Forrester expects online retail sales to reach $44 billion during the months of November and December 2008, a 12% lift over the previous year and the slowest growth to date.

This year’s weakened growth is indicative of macroeconomic factors catching up with formerly resilient Web buyers, Forrester says.

While consumers remain pessimistic about the health of the US economy, online shopping drivers of convenience, selection, and perceived value will continue to attract buyers to the Web this holiday season.

“While eCommerce has traditionally been resistant to negative offline trends, an unprecedented financial crisis has reined in the optimism: 45% of online consumers plan to buy less overall this holiday season due to uncertainty about the US economy, up from 20% in 2007. While the online channel will not be immune to a tightening of consumers’ belts this holiday season, Forrester projects that overall online holiday spend will reach a healthy $44 billion in 2008. Although this represents a deceleration of spend in the Web channel, 27%% of US online consumers still expect to spend more online this holiday season than last year.”

For details see Outlook For US Online Holiday Sales, 2008.