I believe Apple has an agreement with Akamai. Here are some data points for just one household with two macs, two iPhones, and two iPads www.isg-apple.com.akad

I believe Apple has an agreement with Akamai. Here are some data points for just one household with two macs, two iPhones, and two iPads www.isg-apple.com.akadns.net 571 requests in the last day us-courier.push-apple.com.akadns.net 558 requests in the last day .akamai.net 709 requests in the last day and .akamaiedge.net 1967 requests in the last day -- I believe Google just uses *.l.google.com (my open dns says 1202 requests in the last day)