I am interested in using Plex Media Server to stream local content from my PC to my Xbox one. Since Plex connects through my browser, this won't show as data usage will it? All content is stored locally on my PC.
It won't use any data streaming local content to local clients, but what I would watch out for is the server going online to get info about what you're streaming or content you've put on your server. I've used XBMC, now Kodi for two or three years and I had to lock it down to keep it from doing this.
Alan, the plex media server does access the internet to fetch things like album art when it scans your media library. I do not think this would amount to a lot of data usage, but it will be more than zero. if you are comfortable with Linux, minidlna works well for streaming your media files, but does not do any on the fly transcoding like Plex does. XBMC as mentioned above is also good.