When I recently arrived in New York (JFK) from Europe there was a line at the immigration that looked 3-4 hours long. At the beginning of the line an agent had a look at my passport (I am a Russian citizen with B1/B2 visitor visa) and directed me to a machine where I scanned the passport and my fingerprints. After that, they directed me straight to a border officer and a few minutes later I was already on the AirTrain to Howard Beach.
This would be the end of the story were I less curious... but why? I can't think of any reason that would set me apart from everyone who went into the long line. It is not citizenship: I saw a lot of different passports in the long line, including Russian ones (and I'd expect that Russians face on average more scrutiny, not less).