The best Web merchants use a code to scramble the numbers in transmission. If the lock looks broken, the transmission is not secured. It should appear broken most of the time, except when credit card and other sensitive information is being requested. But many sites don't use this system, and even the best codes can be cracked. Many veteran Net shoppers shrug off the risk of credit card fraud as no worse than having the slips lie around restaurants and department stores.
Returns are harder than in regular stores, and consumers generally bear the shipping cost.
There are privacy issues, too. Consumers worry that revealing their shipping address and buying preferences to Web merchants will bring them more junk mail. Or worse, trigger a new wave of calls from telemarketers. Under pressure from privacy advocates and the federal government, most Web sites posted statements this year clarifying to whom they sell or provide customer data. Many also tell consumers how to remove themselves from mailing lists.