According to a recent industry survey, the fastest sales growth for 13 years was reported for the UK’s online retailers in September 2013. It indicated that records stood to be broken once again in this year’s Christmas shopping period. But who won the quest for increased customer satisfaction?

Based on our analysis of customer satisfaction across the UK’s top 40 online retailers (by site traffic) - from over 10,000 customer surveys collected during the prime Christmas shopping period in November and December - yet again it wasn’t the grocery sector.

Disappointingly, 2013’s findings indicated a slight, but meaningful decrease in aggregate satisfaction from Christmas 2012 to Christmas 2013 (from 74/100 to 73/100) - the first time since the survey was launched we have seen a fall.

While a one point drop sounds small, the direct effect satisfaction has on revenues and profitability means that even this slight reversal of fortune has the potential for significant negative impact. Indeed, research conducted across the top 100 US retailers shows that, for an individual company, a one point increase in satisfaction is likely to lead to a 10.6% increase in revenues generated on the web.

Any retailer registering an average or lower score is risking loyalty, recommendations, sales, and market share. By this measure, asda.com and tesco.com are only just hovering above the aggregate score - both have dropped two points since 2012 and lie at 14th and 19th respectively. Asda Direct has also dropped a point to 76 but takes 6th place. A fall across both arms of the business is something that Asda needs to investigate.

On a more positive note, it’s great to see marksandspencer.com improving by two points to take fifth place in the index with 77 points. Tesco Direct gained a point to earn a score of 75 and take 11th place.

To sum up, it appears that online customers are proving harder to please, but this represents an enormous opportunity to strengthen loyalty for retailers that can build a satisfaction lead over their competitors.

Larry Freed is CEO of customer experience analytics provider ForeSee