RETAILERS did their best to entice shoppers to splash their cash on Black Friday, November 28th, the traditional start of the holiday shopping season. Massive discounts probably helped to get the shoppers to open their wallets and purses. Shoppers spent $534m online on Black Friday, up from $531m in 2007, according to comScore, a market-research firm. This compares with a drop in online retail spending of 4% in the first 23 days of November, when shoppers spent $8.2 billion, down from $8.5 billion in 2007. Now merchants will hope that shoppers continue to spend on Cyber Monday. Some 84% of retailers say they are offering a promotion to entice shoppers, up from 70% last year. But canny buyers know how to make their money go farther. Traffic to coupon websites shot up by 33% in October compared with a year earlier.