Foursquare launched a developer preview for Connected Apps — that is, “developer-crafted experiences that exist within Foursquare” — for iPhone and Android smartphones. (Blackberry’s on the way.)

Foursquare’s own blog: This opens up a ton of possibilities, all around interacting with people’s experiences while they’re having them. For instance, Eat This, Not That can suggest healthy dishes the moment someone checks in at a restaurant. Or The Weather Channel can tell people the forecast when they check in to a new city.