After launching one year ago, New York City-based Sonar unveiled a major update today that makes it easier than ever to find friends and like-minded people nearby — all with the goal of becoming a “Here-Now” mobile social network.

When it launched, the free Sonar app tapped Facebook, Twitter, and Foursquare data to see how you were connected to people checked into specific locations. Today, Sonar is adding a slew of new features to build on its promising start, including “Sonar Presence,” which allows the app to run in the background and automatically alert you of interesting people nearby, and “Sonar Status,” which acts like a tweet just for friends nearby.

You’ll now be able to send private messages to people from within the Sonar app, and the company tells me it will also alert you of when your actual friends are nearby.

All of the new features serve to make Sonar even more compelling, especially compared to overly-hyped people discovery apps like Highlight and Circle.

Whereas Highlight is focused on connecting you to people actually using its app, Sonar does a better job of highlighting people that you’re connected to on Facebook, Twitter, LinkedIn, and Foursquare, even if they’re not using the Sonar app. It may just be a personal thing, but Sonar fits far better into how I’d like to approach people discovery. The first time I opened the newly updated Sonar app, I found people I was connected with at some of my favorite haunts. Few apps have proven their usefulness to me so quickly.

Thanks to Sonar Presence, the app is no longer limited to finding people checked into locations. Sonar is also making a bigger push now to connect you to friends, or people you may know via an acquaintance, rather than finding complete strangers. That removes a big creep factor from social discovery, and it opens the door for you to be better organized with people you actually care about.