I disagree, It's already well documented how the US government follows social networks and decline people entry over comments made[1].

Where this case differs is that the comments were over private messages - which means that the intel would have been collated covertly. So the real question is whether this is another piece of the PRISM jigsaw or just a sensationalist article cashing in on the hysteria that the NSA leaks have generated.

[1] http://www.huffingtonpost.co.uk/2012/01/30/leigh-van-bryan-a... (though in that case - I actually blame the visitors for posting dumb comments rather than the US government)