1. A computer-implemented method comprising: caching, in a local stream store of a local proxy, one or more streams of data transmitted over a wide area network to a remote proxy; chunking a flow of data received from a device into a plurality of chunks in a sequence; and selectively indexing a portion of the plurality of chunks in a chunk index maintained by the local proxy based on locations of the plurality of chunks in the flow, wherein a first number of chunks located closer to a beginning of the flow and farther from an end of the flow is indexed at a higher frequency than a second number of chunks located farther from the beginning of the flow and closer to the end of the flow, and wherein the chunk index includes a plurality of chunk index entries referenced to the one or more streams stored in the local stream store, the portion of the plurality of chunks comprising less than all of the plurality of chunks.