Though perhaps not the best timing, Foursquare announced June 28 - the second day of the Google I/O conference - a new service called "Connected Apps." It allows apps to be integrated into the service. So, for example, when someone checks into a restaurant, recommended dishes are immediately shown, and a developer preview is available now.

25,000 developers use APIs to build apps for the service, Foursquare revealed on its blog. Foursquare described Connected Apps as dynamic apps depending on where a user is, citing The Weather Channel as an example where it "can tell people the forecast when they check into a new city." It doesn't sound anything drastically different to how weather notifications work on current smartphones, which is GPS-based so the current location updates.

"Whatever you build, one of Foursquare's 20,000,000-strong community can connect it to their account and see your messages in their post-check-in screens," Foursquare added. Foursquare also shows the apps contributions, so other people know about the app, by providing a link. A new story is also created when an app is connected for the first time.

"It's a developer preview because we want to see what you should do, what our users are looking for, and where we should take the platform," Foursquare also said. No release date for consumers was given.

Foursquare added on its developer blog that apps can send custom replies to users when checking into a certain area, and users tap the notification to head into the Web or mobile app. Replies can be up to 200 characters, and "specify a URL and then contentid." Developers can then send users to either of the aforementioned apps to send the relevant content to the user, such as recommended dishes or current weather.

Foursquare also announced a range of new partners, including Foodspotting, Instagram - which allows users to share Instagram photos on Foursquare to be seen by friends - and Path.

Connected Apps is currently available on iOS and Android, and soon BlackBerry devices. No support for Windows Phone was announced. A "larger" launch will happen later in 2012.