Norovirus outbreaks severely disrupt healthcare systems. We evaluated whether Webs?k, an internet-based surveillance system using search engine data, improved norovirus surveillance and response in Sweden. We compared Webs?k users' characteristics with the general population, cross-correlated weekly Webs?k searches with laboratory notifications between 2006 and 2013, compared the time Webs?k and laboratory data crossed the epidemic threshold and surveyed infection control teams about their perception and use of Webs?k. Users of Webs?k were not representative of the general population. Webs?k correlated with laboratory data (b?=?0.88-0.89) and gave an earlier signal to the onset of the norovirus season compared with laboratory-based surveillance. 17/21 (81%) infection control teams answered the survey, of which 11 (65%) believed Webs?k could help with infection control plans. Webs?k is a low-resource, easily replicable system that detects the norovirus season as reliably as laboratory data, but earlier. Using Webs?k in routine surveillance can help infection control teams prepare for the yearly norovirus season.