Christmas cracker as rival varieties came on the market. The other elements of the modern cracker—the gifts, paper hats and varied designs—were all introduced by Tom Smith's son, Walter Smith, to differentiate his product from the rival cracker manufacturers which had suddenly sprung up. Tom Smith merged with Caley Crackers in 1953. A memorial water fountain to Tom Smith and his family stands in Finsbury Square, London. The longest Christmas cracker pulling chain consisted of 1081 people and was achieved by The Harrodian School in Barnes, London, UK, on 10 December 2015. Passengers on commercial flights in the United States are explicitly
Item-item collaborative filtering Item-item collaborative filtering Item-item collaborative filtering, or item-based, or item-to-item, is a form of collaborative filtering for recommender systems based on the similarity between items calculated using people's ratings of those items. Item-item collaborative filtering was invented and used by Amazon.com in 1998. It was first published in an academic conference in 2001. The authors of that paper, Badrul Sarwar, George Karypis, Joseph Konstan, and John Riedl, won the 2016 "Test of Time Award" for their paper "Item-based collaborative filtering recommendation algorithms". The International World Wide Web Conference committee stated that "this outstanding paper has had a considerable real-world impact".