Nobody ever seems to define this!

Hey,

If I am a host it would be : outbound + inbound
If I am a client, it would be : outbound only

:D

I include any data transfer between the customers virtual server and any remote computer, irrespective of direction of transfer, because whether its inbound or outbound it is still a transfer of data. Its a simple matter of semantics.

Most hosts I have seen are only charging for the data transfered from the server to a web visitor.

Noefree

I've always considered data transfer to include both incoming and outgoing, but some hosts only charge for outgoing.