What can MultiTES4 actually do?
The current version (being only an alpha) is pretty limited in it's capabilities. It supports only 2 people running around Cyrodiil. The other players in the game are represented as NPCs to each individual on their computer. The NPC will move and travel to match the players that are connected to the server.
What can't MultiTES4 do?
At the moment, the following haven't been implemented: time/day/year synchronisation, quest sharing, deathmatch, cell/world synchronisation, err pretty much everything else you can think of. Console commands aren't blocked, either is fast travel. Animations aren't shared, neither is inventories or attributes. I wasn't kidding when I said it was the basics.
Still as a first step, I think it's grand.