Oran Viriyincy at Seattle Transit Blog put up a post because he found an ad on Seattle's light rail. It is the first ad he's ever seen on a light rail car, and it is an ad for apartments. Viriyincy notes:

Last November, Clear Channel Outdoor was awarded a contract from Sound Transit to manage all revenue-generating advertising for the agency. This likely explains the absence of ads in the first few months of service of Link. Even after November, there’s a dearth of advertising on Link.

Please allow me to LiveJournal for a moment: I am generally anti-advertisement in public spaces. One time, someone yelled at me because I took a sloppily pasted-up ad for a Budweiser energy drink off of an attractive, old-fashioned wrought-iron phone booth in Pioneer Square. "At least it's a nice thing to look at!" he shouted, adding, "At least it's not fucking graffiti or something!" I did not—and still do not—regret pulling the ugly thing from off of the pretty thing.

That said, I am very pro-ads on trains and at transit stations. I love taking the train in New York or Boston or San Francisco, where ever-changing ads for movies fill the background with some color. I even like those weirdly non-descriptive fashion ads, with pretty, greasy people staring off into the distance, with a logo I don't recognize off-centered at the bottom of the ad. They're transitional background images, swapped out biweekly or once a month, and they suggest a cultural conversation that isn't necessarily an important one, but the conversation passes the time while you're waiting to go home.

I think Sound Transit has done an awful job of commercializing Link. There should be coffee carts and (yes) newsstands all around these light-rail stations, and garish signs should be trying to sell us stuff. It's part of urban life, and it's a sign of a healthy transit system. Times are tough, sure, but someone isn't doing their job if they're not selling ads in spaces that are seen by thousands of captive eyes every day.