Somebody told me that the file transfer feature
of Yahoo IM was that one client uploads the file
to a temporary WebDAV-like storage space on a
web server. Then, the other client downloads
it from the same place.
Right; my point being that this server is part of the Yahoo IM system. This shows a different mechanism for extending the oob namespace to bridge firewalls. The drawbacks are that it might use a lot of disk space on the server, that it basically doubles the transfer time, and that it's quite specific to file transfer and doesn't allow for other types of P2P communication. It is pretty simple, though.
--Jens
