Access: [3.5.2.3]: potential header (underline)
(Priority 2)

Cause:

If a lead sentence or paragraph is underlined consider converting it into a header. If a text element occurs within a paragraph and the paragraph is less than ten words containing only text items or formatting elements it is also potentially a header.

Testfile:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
	"http://www.w3.org/TR/REC-html40/loose.dtd">
<html lang="en">
<head>
<title>aert1.0/3.5.2</title>
</head>
<body>
<p><u>This may be a header.</u></p>
</body>
</html>

References:

W3C WAI: http://www.w3.org/WAI//
HTML Techniques for WAI 1.0: http://www.w3.org/TR/WCAG10-HTML-TECHS/