21. The processing system of claim 18 , wherein the processor is further configured to: receive metrics from the client device indicating whether the prerender candidate was selected when displayed; and use the metrics to identify future prerender candidates in response to subsequent search queries.
21. The processing system of claim 18 , wherein the processor is further configured to: receive metrics from the client device indicating whether the prerender candidate was selected when displayed; and use the metrics to identify future prerender candidates in response to subsequent search queries. 22. The processing system of claim 21 , wherein the metrics are at least one of whether a selected link was prerendered or a load time of the selected link.