Consumers could be forgiven for thinking that they need an accountancy qualification simply to go shopping. Not only are they bombarded with data ranging from price per unit of weight to nutritional values, ingredient quality and the CSR brownie points accrued with each purchase; they're also expected to juggle all this information with buy-one-get-one-free offers, cashbacks, loyalty points on store cards and discounts on future purchases. There's also the problem that being the first to disclose information in controversial areas can attract unwanted publicity. Information is not only proliferating on packaging. A new law of marketing physics has evolved: every claim you find on the web generates an equal and opposite claim on another site.