Today, Usenet has grown to enormous proportions. Sites that carry the whole of netnews usually transfer something like a paltry sixty megabytes a day. Of course this requires much more than pushing around files.
News is distributed through the net by various transports.
The historical medium used to be UUCP, but today the main traffic is carried by Internet sites. Any article generated or received by the local news system is forwarded to them, unless it has already been seen at that site, in which case it is discarded. On the other hand, the newsgroups exchanged may be limited by both the sending or receiving system. The sheer number of articles usually requires that improvements be made to the above scheme. On UUCP networks, the natural thing to do is to collect articles over a period of time, and combine them into a single file, which is compressed and sent to the remote site.