I used to install those servers! They were through the Akamai network. The more people that watch a movie, the more bits of it that get cached so the ISP doesn't have to go out to the backbone provider to grab data. The tech was essential to allow Netflix to operate back in the 1.5Mb DSL days.
The real question would be: Is every episode accessed frequently enough to be worth caching in the closest storage tier at your ISP? Last I checked, the show isn't even HD, so the buffering might indicate that Netflix servers are having to fetch some of the content from deeper / slower tiers of storage.