There was some follow up work as well: http://blog.dinaburg.org/2013/09/bitsquatting-at-defcon21-an...
And I am beyond certain they were not typos; the requests were for long URLs that no one would be typing by hand. A few were for services that humans never enter urls into (like the Windows crash reporter).
But I'm not entirely convinced that most of these requests weren't just typos. Though those requests with mismatched Host header surely were true bitflips.