Most of my Excel work is proprietary, and permission has not been sought by me to publicly display whole or partial files.
Demonstration via webaccess/in person can be done with no exchange of files or data.
PROBLEM 1: The webmaster tried to post an interactive Excel spreadsheet online and was told that many of his visitors could not use it. He found out that his visitors were required to have the "Microsoft web components" installed to use the spreadsheet! Other options require visitors to have excel equivalent software.
RESOLUTION: The calculation form below is an Excel spreadsheet that I adjusted and converted to HTML so no software is needed by the visitor. (The company I made this for gave permission for me to use it as a sample or in a tutorial.)