When my flight from Frankfurt landed in Atlanta yesterday, there was an announcement made that Customs and Border Patrol agents would be meeting the plane, and all passengers must have their passports ready upon deboarding. I've flown into Atlanta from Europe on numerous occasions over the past few years, and this had never happened before.
Upon hearing the announcement, I was pretty sure I knew who they were looking for. One row behind me were two men of distinct Arabic (or as the Brits are saying now, "Asian") appearance. As luck would have it, they were directly behind me when I was getting off the airplane. I snuck a glance at their passports, and while I couldn't quite make out the English writing on the cover, there was definitely Arabic (or similar) writing on them.
The two CBP officers impatiently waved me through without even asking for my passport, and went directly towards the two gentlemen behind me. I watched from the escalator as the officers looked at their passports, then escorted them down a hallway to the side of the escalator.
While these guys were in all likelihood perfectly innocent, it's good to know that the CBP are monitoring who's on international flights entering the US and giving certain visitors the extra attention they merit.