You therefore have to be careful about how you present your text. This section will discuss the problems that may arise from a mismatch between the sending and receiving software, and show how to avoid them. Some email reading software only understands plain text. Italics, bold, and color changes will show up as control sequences in the text. Hey, I loved the presentation you gave to Jack this morning.
Web documents are particularly difficult to read with older email programs.
This allowed some free space for error correction - something important when computers were calling each other with modems. However, the net is a different place now. E9gonde sur les arbres. After all, you might not ever use umlauts. Even if your correspondent's software knows how to convert codes back to extended characters, different computers have different symbols for the same codes.