if you're concerned about the resulting size of the shared workbook,
remember - when you share a workbook, you have the option of tracking all
the changes.  this feature can be turned off (see the advanced tab under the
tools-share workbook menu) however, you will not be able to "see" the
changes made to the workbook.

have a look at the advanced tab - you can "tweak" the history to suit your
needs.