1. A system, comprising: one or more memories; and one or more processors coupled to the one or more memories, wherein the one or more memories comprise program instructions executable by the one or more processors to: receive, at a computer system from a plurality of remotely-located clients, wherein the computer system is separate from the plurality of remotely-located clients, quality metrics for a plurality of streaming content sessions, each streaming content session including the streaming of electronic content from a content source of a plurality of content sources to a remotely-located client of the plurality of remotely-located clients, each quality metric indicating a measure of quality associated with playback of the streamed content, wherein the computer system is separate from the plurality of content sources; and for a particular remotely-located client of the plurality of remotely-located clients, wherein the remotely-located client is to participate in a given streaming content session: identify a particular subset of quality metrics, of the quality metrics received from the plurality of remotely-located clients, which are associated with at least one property of the particular remotely-located client; generate, at the computer system separate from the plurality of remotely-located clients and the plurality of content sources, a ranking of content sources based on the particular subset of quality metrics, wherein a given ranking specifies multiple content sources each ranked on expected quality of a streaming content session between the content source and the particular remotely-located client; and provide the generated ranking of content sources, from the computer system separate from the plurality of remotely-located clients and the plurality of content sources, to the particular remotely-located client for use in selecting a content source for the given streaming content session.