Apple, Walmart and Amazon were the top three most-visited online retailers on Black Friday last week.The latest ComScore figures reveal that Apple saw a 39 per cent increase (year-on-year) in traffic to its retail website - one of the biggest traffic increases among all retailers. Amazon traffic climbed 28 per cent,For the holiday season-to-date, $10.57 billion has been spent online, marking a 3-percent increase versus the corresponding days last year. Black Friday (November 27) saw $595 million in online sales, making it the second heaviest online spending day to date in 2009 and representing an 11-perc