> With the location information it is possible to correlate the exit information via pattern matching, though it would take considerable analysis, this can be done by logging volume and timing information on the two sides. I am sure there are even better techniques to analyze exit/entry correlations, especially if you're not using a secure browser.

I've thought the same. But I've also thought that if this is indeed possible, why does Silk Road still exist? Or does this analysis only apply Tor clients connecting to websites, and not Tor hidden services?