I just ran into the "problem" of the S3 Firefox Organizer not recognizing folders created by s3sync today. The ff extension designates folders by appending '_$folder$' to the node name. My shameful hack to get these two tools to live together was to add a check for nodes that are 38 bytes long(the length of the s3sync meta data) and treat these as folders. I would like to just check the contents, but that would require reading each node to determine if it is a directory. It's not a perfect solution, but it works for me.

Is not having a standard way of identifying folders going to be a problem when more and more tools come out for managing S3? It appears that way to me.