problems

Lessons:

Make sure pathologic is setting the right root URL before boost runs. It seems the very first cron run pathologic still has the old site's information, or rather more likely the page cache or the node cache still has the old information, and these caches must be cleared immediately.

Never, ever have boost set to gather 1,000 pages at once-- it can try to run them all simultaneously and take out your server.

Even when you have boost, don't forget to turn back on the basic performance optimization settings when going live: CSS and JS compression.

.section-aboutus .date-display-single {
  color:#2d95c1;
}

.section-aboutus .date-display-single p { margin:0px; padding:0px; }

Can that second CSS rule call the p tag into being?

Definitely one of the freakiest things I've seen. The source code contained no p tag within the span. The code shown by Firebug and Safari's inspector both had the the paragraph tag.

Actual source code:

<p>Tri Star Pictures <span class="date-display-single">2009</span></p>

Had this suddenly up in the content where it shouldn't be, and nothing that should have loaded was there.
=0)document.write(unescape('%3C')+'!-'+'-') //-->

apparently caused by Omniture, since that exact code occurs here (but really it was a stupid quotation mark not closed error) --

"exanded" elements of a menu-item-rooted tree aren't expanded
http://drupal.org/node/398888

Working modified function (the patch has more):