I'm not familiar with Blossom servers, but I know they're used to serve media from for Nostr. In the slide it mentions distributed blobs. Does this means it uses the bitTorrent protocol?
Discussion
Blossom servers are normal webservers with prefifned endpoints. Files are stored and accessed using their sha256 hash (as filename).
If you then upload a picture and reference it in you nostr post for example. People can fetch that image not just from the server you referenced but from any other blossom server that holds a copy of the file.
And because the filename is the hash you can guarantee that the file hasn't been meddled with (malware) by a server you get it from.
So no, BitTorrent is not involved and it's not a peer-to-peer system.
That is interesting. Thank you for explaining. Is it a cdn-like setup with caching?
Yes, you get a bit into semantics here but my view of it is that blossom is the procol that by its nature allows easy formation of a CDN.
It's unlike legacy CDNs (like CloudFlare) where you need to trust one large party.
Caching and saving in blossom are the same, really. You can keep all videos/images you watch on nostr for 2 weeks and then drop them. In the meantime you can allow friends/family to load the files from your blossom instead of the original poster which might be on the other side of the world...