Apple remains the category leader in attracting unique visitors to its Web site, despite a dramatic surge in visits to in the last month, according to Nielsen/NetRatings. “In the week ending Dec. 12, compared with a month earlier, the number of unique visitors to Apple’s site declined from 4.9 million to 4.6 million. Meanwhile, Dell climbed from 2.7 million unique visitors in November to 4.1 million in the most recent period.”