Jake Brutlang (View Paper → )
Experiments demonstrate that increasing web search latency 100 to 400 ms reduces the daily number of searches per user by 0.2% to 0.6%. Furthermore, users do fewer searches the longer they are exposed. For longer delays, the loss of searches persists for a time even after latency returns to previous levels.
This is the paper that proved the importance of speed on the web. I still see people reference this paper today. Every time you perform a search on Google, it proudly displays the number of results and the response time (0.45 seconds for my last query).