Foursquare’s Alex Rainert Talks iOS 5: The Technology Has Finally Caught Up With Our Vision

This will go great with our Sonar

The newest version of Apple’s mobile operating system rolled out today, and foursquare is leveraging the new technology to launch Radar, the first passive feature the company has ever released.

“Up till now, you had to open the app to learn what was going on around you. A lot of times you had to check in before you saw what friends were in your area,” said Alex Rainert, foursquare’s head of product. “Now we can deliver users information that is contextual and relevant without them having to do anything at all.”

So for example if a foursquare user is in a new part of their city and walks close to a restaurant on their “To Do” list, the phone can ping them with an alert. During a night on the town, the Radar feature can sense when a group of friends has checked in close to a user and give them a heads up.

“This is the next stage in the evolution of foursquare,” said Rainert. “The hardware and software have finally caught up to our vision of making it easy and fun for users to get more out of the world around them.”

Along with foursquare’s new List feature, this goes a long way towards making the service a powerful tool for travelers who want help exploring a new locale. And for heavy users who don’t mind a few push notifications, this turns the app into a powerful, passive sensor for the nightlife around them.

Now if only we could get iOS5 to download…