When using localhost:5005/8361c37efa52cb2809f459fcf2559966dd384787f7ea6f0475c168ac069a31fb/hello:latest as the URL for whalesong, you rely solely on hypercores and IPFS. However, the long public key of the hypercore (8361c37efa52cb2809f459fcf2559966dd384787f7ea6f0475c168ac069a31fb) is not very friendly for humans. Therefore, whalesong also supports human-readable organisation names, by using dat-dns.
In short, this means that the URL above can also be written as:
localhost:5005/whalesong.club/hello:latest
The works by adding a /.well-known/whalesong file to the webserver on whalesong.club.
The /.well-known/whalesong file has the contents
whalesong://8361c37efa52cb2809f459fcf2559966dd384787f7ea6f0475c168ac069a31fb
ttl=3600
which points to the desired public key.