Did you Ever needed to track what other people updated on your spreadsheets?
Just activate the "track changes" under tools. (Excel 2003) .
Then send your spreadsheet out to several people.
Once you get the response back. you can merge all copies into one as a grouped update.
Note: don't forget to activate "track changes" BEFORE you send out your original, since Merging is only available on Shared copies...
If anyone uses Office 2007, please leave a comment with the option where you can find this in Excel 2007.
