January, the month of unlikely stories, is back, attracting incomparable interest to its so-called like-for-like sales reports.

But the periods selected (anything from 13 weeks to 13 days, ending before or after Christmas) and the definitions used (same stores or same footage; all stores or excluding infant/cannibalised stores) are of such diversity that they defy meaningful comparison.

What about like-for-like profits? Who went on Sale, when and at what cost?

In France, such questions do not apply; quarterly sales reporting is the universal norm and, les Soldes, by law, cannot commence before January 9, anywhere – including online.

What a difference the Channel makes: 8 per cent of the British population reportedly shopped online on Christmas Day, spending 269 per cent more than 2006 – at heavily discounted prices.

The internet adds another twist to the like-for-like conundrum: should online sales be included? Probably yes; multichannel retailers should be judged across all their activities. But this should be recognised when comparing them to pure bricks-and-mortar rivals. Core market share is arguably a more critical indicator than enhanced like-for-likes.

If included, what should online retail sales comprise? What about eBay, which is sometimes included in Germany, or the 3 million tracks downloaded in the UK in the week before Christmas? And when? For example, should online booksellers account for sales of electronic gift tokens when purchased or redeemed?

Gift cards are the hot topic in the US. Some forecasts had 65 per cent of Americans planning to send gift cards this Christmas, with sales potentially hitting US$35 billion (£17.74 billion) – up 20 per cent on 2006.

Gift card malls are proliferating: Safeway’s Bluehawk gift card subsidiary expects to contribute US$100 million (£50.7 million) to earnings this year and projects revenues of US$20 billion (£10.14 billion) by 2012. Bluehawk has recently set up its stall within Morrisons and the UK overall is likely to see dramatic growth in gift card activity this year.

These are not the boring vouchers of yore. They are packaged with marketing flair and can be image- or audio-equipped. They might be green cards or good cards (gifting to a charity), restaurant cards or grocery cards – medical cards, even.

Such cards are the icing on a more substantial, highly topical cake: the credit crunch. In its Precious Plastic 2008 report, PwC tracks the rise of debit over credit cards (the former now accounting for twice the expenditure of the latter) and anticipates consumer behaviour as the economic environment continues to toughen.

Pre-paid cards in general, contactless payment cards and the new reloadable mobile cards not only signal the ongoing flight from credit, but could herald the beginning of the end for cash.

By Michael Poynor, chief retail adviser, PricewaterhouseCoopers