This can be seen in the signature block, ie name(new line) position...
Below is from a customer email

Editor frequently makes a mess out of cut and pasted email messages. Wikimarkup says two adjacent lines of text get concatenated into one line. When cutting and pasting into the wysywig editor, it shows things correctly formatted as multiple lines with proper line breaks. Even the preview shows the line breaks properly. But after save, everything runs together.