The "notes" (non-video content) are hosted on relays like everything in Nostr. The media is hosted on regular web servers and it says you can host it anywhere.

The "notes" (non-video content) are hosted on relays like everything in Nostr. The media is hosted on regular web servers and it says you can host it anywhere. It seems like most of the videos are hosted here: https://nostr.build/ https://nostr.build/ Which is a paid service backed by AWS S3