UK internet searches for discount vouchers have increased by 133% over the past year, according to Hitwise UK.
Visits to voucher websites have also increased by 45% over the same period, and UK internet users searched for over 20,000 variations on the term voucher, during the 12 weeks ending 15 November.
Hitwise said UK consumers are more likely to visit retailers offering discounts and sales in the run up to Christmas.
Marks & Spencer's recent 20% off sale generated one in every 33 UK internet visits to an online retailer and ranked third behind Ebay and Amazon in Hitwise's Shopping and Classifieds category.
The retailer almost doubled its share of visits to the Department Stores category to 15.72% (from 8.32% the previous day).
During November online retailers received 5.47% of their UK internet traffic from social networks, up from 4.3% the previous year, while 3.87% came from online email services, this was lower than the previous year when 4.9% of online retailers traffic came from Email Services.
Robin Goad, director of research for Hitwise, said, "Fashion is currently the fastest growing retail sector online, and it now accounts for over 10% of all UK ecommerce traffic. One of the key factors in this success has been the way that online fashion retailers have built user communities on social networks."