Groups.Drupal <strong><i>...</i></strong> -- missing style

I had to edit my post because I simply cut and pasted the Allowed HTML tags... this created tags, but it also failed to create proper XHTML. Tags left open where carried on outside of the content, and into the rest of the Groups site. Essentially no check or correction was made by Comment to make sure I closed the tags I opened. I am searching for the tag that is not being closed. <h1> <h2> <h3> <h4> <h5> <h6> <blockquote> are not used. <em> <strong> <code> all are used, but if I dont close them I screw up the rest of the page...

Here is an example of the HTML inject <sup>using <em> ^{without closure... I hope this works... I will close the tag in my next reply... there is a few that fail...}