I agree with bumpski above. While it is all well and good that the AdSense JS files are sent to users gzipped, but there is way too much serialization with AdSense scripts with way too many JS files being requested. Also some of the more "static" elements of AdSense ads need to be made cachable (e.g. the Google logo, navigation arrows and any static JS files so that this stuff is cached from site to site that has AdSense ads. Google reducing AdSense serialization, streamlining JS code and making as much cachable as possible could help shave up to one second off of my page load times.