I didn't post anything about this story when it first occurred because others had covered it pretty thoroughly, and because I at first didn't recognize its significance:
The FBI is warning police nationwide to be alert for people carrying almanacs, cautioning that the popular reference books covering everything from abbreviations to weather trends could be used for terrorist planning.
In a bulletin sent Christmas Eve to about 18,000 police organizations, the FBI said terrorists may use almanacs "to assist with target selection and pre-operational planning."
It urged officers to watch during searches, traffic stops and other investigations for anyone carrying almanacs, especially if the books are annotated in suspicious ways.
It seemed like a silly example of the FBI implementing an arbitrary security step of dubious value. As Teresa Nielsen Hayden pointed out, it also seemed to show a worrisome lack of imagination on behalf of those charged with our domestic security:
What scares me, though, is how specifically the FBI has targeted almanacs, and how they haven’t mentioned travel guidebooks, high-resolution terrain maps, architectural guides, government directories, maps of underground water, power, and transit systems, lists of major industrial sites, the Yellow Pages for pete’s sake, or any of the other references that might reasonably be used at that stage. …
But then it hit me — almanacs — just like in Back to the Future II!
Maybe the alleged terrorism concerns that prompted this alert were really just an elaborate cover story masking the FBI's real search — the effort to track down and destroy an almanac from the future brought here by a meddlesome time-traveling teen in a fusion-powered DeLorean. That would explain what otherwise appears to be their foolishly narrow-minded focus on almanacs — they're desperately racing to prevent an anachronistic paradox that could cause the fabric of the space-time continuum to unravel.
Anyway, it's just a theory, but it seemed a little less troubling than the idea that our security is in the hands of the kinds of people who see this as a higher priority than, say, port security.