This isn't specific to any particular url, but I've seen it frequently on http://appleinsider.com today. Basically, when I go to the page, none of the content displays. It's downloading just fine, just not displaying it. Sometimes the ads load and nothing else. And occasionally, the whole page loads just fine. Switching away from that tab and back to it causes it to display correctly.
Do you still see this after http://trac.webkit.org/changeset/143490?
This seems to be fixed in the latest nightly, which I assume has the changeset you referenced.