I learned about this on reddit (Have Time Warner Internet but can barely stream YouTube? I did an experiment.), and ArsTechnica.com (Why YouTube buffers: The secret deals that make—and break—online video). TL;DR; Apparently there is some serious backdoor negotiations going on With Google/Netflix and the ISP to deliver their traffic – but when negotiations go bad… ISP act like dicks. That’s the real reason your youtube videos are so slow. The solution? by pass the local caches of videos and download them directly from Youtube.com. 🙂
Solution:
sudo iptables -A INPUT -s 173.194.55.0/24 -j REJECT
sudo iptables -A INPUT -s 206.111.0.0/16 -j REJECT
More read: Have Time Warner Internet but can barely stream YouTube? I did an experiment.
Windows Blocking IP Address or IP Ranges: How to Block IP address or IP range in windows server 2008 by Windows Firewall
Mac OS X users can use WaterRoof to make edits to their IPFW tables (GUI Interface): http://www.hanynet.com/waterroof/
More stuff about IPFW Firwall Configuration for Mac OS X: Configuring IPFW firewalls on OS X