The New York Times is a customer of the bit.ly Pro service. That means NYT-shortened links are assigned under the nyti.ms domain — and this behavior holds true for anybody shortening a link to NYTimes.com. Now, it is also true that bit.ly is not the only URL-shortening service out there, but it remains the predominant shortener. At the very worst, my choice to limit this to bit.ly means I’m underestimating and thus erring a bit on the conservative side (although I do not know how to measure how big of a margin of error that is).