The sign was bullshit.

There’s a particular intersection in downtown San Francisco that features six intersecting multilane streets. A driver unfamiliar with this particularly opaque parcel of the Foggy City has to rely on the 3-foot square sign dangling from a traffic light to untangle the turn lanes, throughways, one-ways, abandon-hope-all-ye-who-enter-ways, and general navigational bad ideas of this specific navigational bad idea.

By the time I figured out which lane I wanted to be in, I was already resoundingly not in it. Instead, I had pitched my fate in with the traffic bound for Oakland, where the urban planners are marginally more lucid and certain residents are inclined to resolve the entire issue by obligingly stealing your car.

That sign hanging from the traffic light was, therefore, bullshit. There seem to be three broad categories of signs: the vitally important, the theoretically useful and the utterly useless.

In this last category are signs like the one detailed above, ones so esoteric that by the time you’ve deciphered them, you realize you needed to have done so approximately 17 seconds earlier and are now shit out of luck. Also classifiable under “useless” are signs that divulge information that you couldn’t do anything with even if you wanted to, such as the timeless “Speed Enforced By Radar.” Similarly, signs that convey information that would be obvious to possum fall under this umbra; my favorite example of this last one was in southern Oregon and read “Tsunami Evacuation Route,” with a sign pointing up a mountain.

In the middle category, the theoretically useful signage, the undisputed king is the “Speed Limit” sign. While awfully good to know in, say, Omaha, this is California and the best we have are polite suggestions as to what speed you would be going if you were an 80-year-old nun on a Vespa.

The really truly essential messages are things like “Road Closed,” “Military Base: No Trespassing,” “Fresno City Limits” and other such indications that, were you to continue in your direction, life would quickly get a whole lot less pleasant.

These categories apply to pretty much all forms of communication, not just the retarded version Caltrans employs.

When you’re talking to your friends, think about what they say to you; a great deal of it is useless beyond assuring you that you’re still worthy of being talked to. Sometimes what they say is theoretically useful: emotional support, offers of or requests for assistance, and suggestions that you might have consumed one too many tequila sunrises. Occasionally, what your friends say is godawfully important: some person wants to have sex with you, some person wants to kill you, or both people have consumed many tequila sunrises and so has your friend, who is about to vomit on you.

Likewise, these categories apply to the news. When you scan a paper, you really ought to be filing the stories into these three categories:

Vitally important: Bush’s plans to suspend the Constitution while he plays cowboys ‘n’ Muslim fanatics with Iraq.

Theoretically important: Bill Simon’s allegations that Gray Davis is corrupt, Davis’ allegations that Simon is corrupt, and my own allegations that the entire Green Party has consumed one too many tequila sunrises.

Useless: the Santa Barbara News-Press.

But most significantly for my average audience, these categories apply to what we learn at college.

If bullshit detectors worked like Geiger counters, Campbell Hall should sound like a swarm of locusts. See, when we’re sitting there, staring at the podium wide-eyed like lemurs on acid, we’re experiencing the equivalent of this column. Some of the information is fact, some is opinion, some is theory and all of it is slanted to comply with whatever angle the professor is pushing.

Thus, as well as taking notes on paper amid doodles of unicorns and genitalia (and, occasionally, unicorn genitalia), we should be taking notes in our head as to what we should latch onto, what we might find interesting and what will lead us to the intellectual equivalent of Oakland. How to distinguish the importance of what we learn is, in itself, the single most important thing we can learn.

Daily Nexus Artsweek editor Alex Benowitz-Fredricks is full of useless information, sunshine and, occasionally, burritos.