When you have a larger chat message in http://chat.meta.stackoverflow.com, the link "see full text" appears. Sometimes it appears when the text is large, but you already see the whole text. Sometimes there's indeed more text.
Whatever's the case, when you click it, more text is displayed, but the linebreaks are removed that were visible in the normal view. These are the linebreaks that can be inserted with Shift-Enter.
A direct link to the source of one such messages is a recent one by me in the XSLT chat room, here's its source and here the permalink.
