Are iframes a terrible idea?

document.domain = 'somedomain.com';

HttpContext.Current.Response.AddHeader("p3p", "CP=""IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT""")

<iframe src="content.html">
    <p>
        This content will only be displayed by browsers that do not support
        iframes. You should provide a link to the content, or in your
        case an alternative way to use your widget.
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</iframe>