Further intrigue abounds in the Am-I-a-filthy-Islamist-terrorist-Frenchman saga. On perusing my logs the day after my visit from the feds, this address turns up amongst the visitors (the link doesn't work):
The person in question had an IP (126.96.36.199) that traced to Washington, on a computer that has a web server (here), and he or she visited the same page as the FBI did, almost exactly 24 hours later. And even although there is no site at www.eop.gov, I have it on good authority that it stands for "Executive Office of the President".
All of which technical jargon leads me to surmise that somewhere in the West Wing, somebody was looking at my site. And even if it's some huge practical joke, the thought of that is rather tickling.