Text in an iframe

Compliant browsers will show the text as a non-wrapped line of plain text in a 500x300 box. Internet Explorer (yes, including the new and improved version 7) will show it in a nicely word-wrapped format complete with go-nowhere hyperlinks. Why? IE and Windows see it as HTML because of the mark-up that's in the text, despite it being sent by my server as text/plain.

For some reason, the Windows beta (3.02) version of Safari wraps the text to fit in the iframe. Not sure if the native Mac version does this.

Text excerpted from Wikipedia's article on the Coast Banksia.