There are a couple of efforts for exporting data for viewing elsewhere that use a 3rd party program loaded onto the computer (
Guild Sales Assist and
IGOR (Research)) but those are essentially export-only. To reliably read data in from an external source you'd pretty much need the user to quit/restart the game.
There are also a few that function by generating a URL then asking the user to copy/paste that into a browser. I suppose you could also make it to copy/paste text back from the site to sync, but it's far from automated.
Mailing would probably be the easiest if you want low-frequency (1-2 times per week) updates that don't have to go into effect immediately. If you want quicker, you're pretty much limited to prefilling the chat box and letting the user submit it.