The street corner, quietly rewired.

Stand at a bus stop in Boston, Fullerton, or South Orange and you might miss it - the flat, sober screen bolted to the sidewalk, flipping through the number 7 bus schedule, tonight's farmers market, a public health notice, and an ad for the coffee shop on the corner. No cables snake into the ground. No hum of a generator. It has been sitting there so calmly that it seems to have always been there. That is exactly the point. This is a Soofa Sign, and it is doing something billboards never learned to do: it is speaking to the neighborhood instead of shouting at the highway.

Most "smart city" technology arrives with a press release and a rendering of a city that does not exist yet. Soofa did the opposite. It arrived as a bench. In June 2014, three researchers wheeled a solar-powered park bench into Boston's Titus Sparrow Park - a slab of wood with an embedded phone charger and a sensor that quietly counted the people who sat down. One week later, that same prototype was at the first White House Maker Faire, where President Barack Obama sat down and used it to charge his phone. It is a very good origin story. It is also a thesis: the smart city does not need to be complicated. It needs to be useful, and it needs to actually exist.

The founders came from unusually good rooms. Sandra Richter, Nan Zhao, and Jutta Friedrichs met around the MIT Media Lab, with Friedrichs bringing a design pedigree from the Harvard Graduate School of Design. All three are women - a rarity in a hardware startup, and one they never leaned on as a gimmick. The legal entity is even named after the idea rather than the product: Changing Environments, Inc. Soofa is just the friendly face the public sees.

Here is the elegant part. A Soofa Sign costs a city very little - often nothing - to install. The city gets free airtime to broadcast transit updates, emergency alerts, wayfinding, and event listings. In exchange, Soofa sells the remaining screen time as measurable, hyperlocal out-of-home advertising. The sensors that once counted people on a bench now tell advertisers who walked past and when. Red Bull, Blue Man Group, the New England Revolution, and Wayfair have all rented that attention. So has the bakery down the street, thanks to a self-serve "Book Now" tool launched in 2025 that lets anyone build a campaign without a sales call.

It is an ad-funded infrastructure model, and it threads a genuinely hard needle: the city wants to be heard, the advertiser wants to be seen, and the resident wants a screen that is more useful than annoying. Soofa put all three on the same corner.