Wow, I'm surprised at the level of assumptions being made in this thread.

Guys, some networking 101:

* The route your traffic takes to get from point a to point b depends on your network/ISP/etc

* The CDN you use when accessing YouTube, et. al. depends on the route you take. The first/nearest CDN to you is (usually, depending on the CDN owner's configuration) the one that will be used.

* The fact that a video loads quickly on one ISP and slowly on another means absolutely, completely, totally NOTHING in and of itself.

To find out if the ISP is to blame or not, you must attempt to access the same CDN server from two different ISPs and see if you get the same problem. The latency will be different, but unless there is a massive bandwidth or latency bottleneck between two hops along either route, the overall bandwidth (for a large enough file) should be sufficient to deduce whether or not the problem is with your ISP or the CDN servers corresponding to the route your ISP is taking to contact Google's servers (the results need to be statistically significant taking into account margin of error and network conditions).

If the CDN is the problem, unless the CDN is actually owned by your ISP, your ISP is not to blame.

In fact, for traditional non-net-neutral throttling, it does not matter which/how many CDN IPs you block. Your ISP should (if they're doing it right) detect your connection to YouTube's subnet and throttle your data rates regardless of which CDN you use. The CDNs in the original article belong to Google/YouTube, not TW. As such, TW would throttle your connection on the way to Google's subnet, not at Google's subnet. They have no control over Google's subnet. The hops past TW's (or whatever ISP you use) servers are not under their control, cannot be bandwidth-throttled by them, and have nothing to do with net neutrality.

The real explanation is most likely poorly-balanced CDN servers. i.e. the traffic going to the CDNs is unfairly skewed towards one or more CDN servers, causing them to serve content to all users of all networks more slowly. By explicitly avoiding said CDNs which are slow on Google's end, you will use a different, less-pounded CDN that can serve your content faster.

Note that I am not even a TW user (Comcast here), but this lynch mob is getting out of control. I expect a higher understanding of basic network principles when I browse HN, and "I can't load YouTube quickly so this means my ISP is shaping my bandwidth, and I need not look for actual evidence to support this claim" does not qualify as such.

That said, yes, it is possible for a cunning ISP to shape your traffic by purposely mis-directing CDN selection, for example, making it so that all their users end up at the same exit (slow) node when contacting a YouTube IP as such effectively YouTube into serving all their content to all the ISP's users from the same CDN node(s), resulting in poor connection. The way to test this would be to map out the routes for packets sent all over, and search for statistically-significant routing anomalies when attempting to pass packets on to Google's network from within a certain ISP.

The CDN you use is often selected off a DNS response for many networks. An easy way to select a different CDN (that may adversely affect your browsing speed due to geo-origination!) would be to use a different DNS server (make sure to flush the DNS cache in your OS and in your browser). This is why it's not advised to use non-ISP DNS such as Google DNS, OpenDNS, etc) unless they're both a) anycast (basically CDN for DNS, your DNS query will go to the nearest geographic location to you) and b) have enough servers distributed around the country so that your anycast DNS request will be resolved near you, so that the CDN based off of DNS will also be physically near you. You can use namebench [0] by Google to query the fastest DNS servers, typically faster means closer as hops then physical distance are the biggest factors in DNS speed, though a shitty DNS server will obviously skew those results.

0: https://code.google.com/p/namebench/