Você pode verificar o novo recursos de colaboração / ao vivo no Office 2010+ :
With Excel Web App one of the goals we set out to achieve was to improve how multiple people work with and share spreadsheets. We wanted to build an experience where people could edit their spreadsheets without having to worry about the file being locked by someone else (unless exclusive access is what you desire, more on that in a moment). Authors can come and go as they please, multiple authors can be editing the same spreadsheet at the same time, and the Excel Web App manages all the changes.
With collaborative editing, it is now possible for two or more people to edit a spreadsheet at the same time. So what happens if these authors are trying to edit the same cell or range of data? Generally speaking, Excel Web App takes a last-person-wins approach. This means that if John and Jane both type a value into cell A1 at roughly the same time, the submission that came in last, from the point of view of the Excel Web App server, is the value that both users will see.