What is "character encoding"?

And why you care

It's hard to do better than this: Wikipedia: Character encoding

Encoding mismatches result in data errors and improperly displayed text. Most of the time, applications protect you from having to know anything about this at all. But when you are transferring data between applications, using files to load databases, etc, problems can occur, and it's often hard to determine how a file has been encoded. When you get it wrong, the results can be disastrous.

That's what this app is for: to examine a file and show you the viable encoding options, and let you choose the one that looks right.