The release notes for version 0.8 of the "Satoshi" client say
"Bloom filter" support in the network protocol for sending only relevant transactions to lightweight clients.
Is this an optional feature or on by default? Does this mean that the client will no longer download the whole blockchain? What is a relevant transaction? Is it only transactions related to keys in my wallet?
Does that mean that I can no longer keep the machine that downloads the blockchain separate from the machine that hosts my wallet (and that I keep offline, copying over the blockchain manually by USB). If so, is there an option to get the old behaviour?