Online research influences sales of more than $400 billion made in stores, according to Forrester Research. The company predicts that figure will exceed $1.1 trillion by 2012.

However, consumers often go to one retailer's website to study a product, and then buy it at another retailer's store. "That means there's a huge opportunity for retailers to engage customers across channels," says Tamara Mendelsohn, author of Forrester's cross channel sales forecast report.

Mendelsohn notes that today the most common products researched online and then bought in physical locations are automobiles, consumer electronics and computers. But she predicts fast growth over the next five years in cross channel shopping for apparel, health and beauty products, home furnishings, appliances, and jewelry.

Following are additional findings from the report:

• 51 percent of online shoppers say they research products on the web and then buy them in stores. And 45 percent say they buy additional items once in the store, spending an average $154 on other items.
• Cross channel shoppers are more likely than the general population to have high speed internet access at home (60 percent versus 40 percent), a college degree, and higher household income ($71,204 versus $56,383).
• Asked why they purchased the product offline rather than on the web, the most common answer was to obtain the product immediately.
• Better price was the primary reason for buying an item from a retailer other than the one whose website was visited, according to 41 percent of respondents. Other reasons were that the online retailer did not have an offline store. Others said it was because they were shopping for more than one product and it was convenient to buy it all at one location.