Huh? Amazon put prime under amazon.com. The domain doesn't mean you have to use the same servers, google already just proxy and load balances behind their exist

Huh? Amazon put prime under amazon.com. The domain doesn't mean you have to use the same servers, google already just proxy and load balances behind their existing domains. They could easily redirect youtube.com to yt.google.com, or serve assets on youtube.com from yt.google.com if they want to have cross domain tracking.