1. A computer-implemented method comprising: under control of one or more configured computer systems, identifying two or more domain allocations to be individually utilized in conjunction with processing a content request corresponding to two or more embedded resources, wherein a domain allocation comprises an association between the two or more embedded resources and a set of domains, wherein the two or more domain allocations are different; and determining a recommended domain allocation for the two or more embedded resources from the two or more domain allocations, wherein the recommended domain allocation is based, at least in part, on a domain selection criterion.