We build planning and scheduling systems in Excel.
Some systems like this material planning example have more than one user, in different locations.
Here is a way to share Excel data across multiple users by using a simple cloud service.
The biggest headache in material planning is long lead-time materials.
Here is a simple tool that gives visibility between a buyer and a factory separated by a lot of water.
Also see an easy trick to connect multiple Excel users on different continents with free data integration over the cloud.