Here's a NYT article on Buffalo:
http://www.nytimes.com/2007/09/13/ny...pagewanted=all
This one says 23 percent of housing units are estimated vacant (there are a number of ways to do this -- for example, the USPS keeps track of the 18,000 or so houses there where nobody picks up mail anymore):
http://www.buffalonews.com/city/spec...icle107563.ece
Things have gotten worse in the US lately but Buffalo and the Rust Belt were in bad economic shape even before the downturn. Lots of people moved to sunbelt areas which were sprawlier but also more economically successful (though perhaps unsustainable).
I've personally been to Buffalo and Detroit. They're very interesting cities but they don't resemble Halifax much. They're almost as different as it gets, since they were big centres of industry when Halifax was a small government/university/shipping town.
I don't know exactly what this person said in the talk. I just pointed this out because sometimes there are weirdly inapt comparisons between Halifax and other cities. It's usually worth looking at them critically.