Invalid HTML?Browser Info Environment
However, the site in question ishttp://textatip.co.uk/. The H3 tag the validator doesn't like is
<h3 class="mailing-list-signup-title">Join Mailing List</h3>
The markup seems okay to me, no doubt I'm overlooking something obvious because I've been staring at it for too long!
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
(no space before transitional.dtd)