When it comes to the continuing creep of advertisements in public space — from movie theater ads and motorized billboards to the obnoxious gas-pump recordings that turn an already wallet-squeezing trip into something even less pleasant — I’m firmly in the anti-proliferation camp. I don’t want to live in the world of Minority Report, where sensors read my identity and beam personalized ads at me on the sidewalk. Still, it’s hard to be 100 percent annoyed at the developers of FogScreen, a new kind of projection system that uses tap water and ultrasonic waves to throw an image onto a curtain of “dry fog.” For one thing, it’s scientifically neat and pretty cool to look at. For another, it seems tailored for use in places — night clubs, convention halls, et cetera — where people are actually hoping to be bombarded with commercial messages. Then again, few technological innovations stay contained once advertisers decide they’re useful. If these walk-through fog messages start trying to sell me soda at the airport, I’ll start shopping for portable dehumidifiers right away. Until then, party-throwers with cash to burn can add some dazzle to events by renting the projectors here.