I don't know of the internals, but on the surface there were three things this did: A torrent creator. This is a simple extension to the REST endpoint of S3,

I don't know of the internals, but on the surface there were three things this did: A torrent creator. This is a simple extension to the REST endpoint of S3, and a specific S3 API, that'd scan a S3 object to create the torrent file, and register the resulting infohash with a tracker. A tracker. Technically not necessary, but with the implementation AWS went with, they needed to run their own tracker to allow peers to discover each other. A seed peer. This was probably a shim on S3 (if I recall correctly, the IP was within the S3 range of IPs). This was responsible for speaking BitTorrent and always having the objects available for clients to download. There are other ways to do this, but I'm sure this pile of tech was a source of abuse and problems for basically no one to use, so I'm not surprised to see it go. I also seem to recall there was a single tracker, and AWS really wants to get rid of single entry points to S3.