Cuil has received widely critical press coverage.[17][18][19] Concerns were expressed about the website's slow response times, irrelevant or wrong search results[20][21][22] and in at least one case, inappropriately pornographic images displayed alongside search results.[23] Danny Sullivan of Search Engine Watch questioned the validity of Cuil's claim that it had the world's largest search engine index and criticized it for focusing on size rather than relevance.[24] Despite reported problems with search results, Net Applications reported that for the last three days of July 2008, Cuil beat Google and Yahoo in the amount of time spent on a site after referral from a search engine, a key metric for relevancy of search results.[25]
According to an interview with a Cuil representative, while other Web 2.0 launches using massively parallel processing might fail with a slow down or crash,[17] Cuil's architecture was responding with incomplete, "less-than-relevant results that then appear at the top of users' pages."[20][22] Cuil's VP of communications Vince Sollitto said the search engine was experiencing heavy first-day overloads and they were "busy putting out fires." Sollitto said Cuil "will only improve with time. It's day one. Traffic is massive. We're new. There are bugs to fix, results to improve."[17]
After the initial critical press coverage Cuil was alleged to have caused issues for some websites, owing to how the Cuil indexing robot polled certain sites. Website owners were reportedly saying the method was not "scientific in any way" and "actually quite 'amateurish.'"[26] Others reported irrelevant images associated with their listing in Cuil's search results.[27][28]
