Yes, I definietly want to know which of my friends are nearby – but I already know that from other more established apps, namely Foursquare and Facebook. I dont care if Sonar is just going to be another random app that tells me which of my friends are nearby. I like Sonar because it suggests new friends, and seemingly inteligently ranks how it prensts people to me.
The real value, the core of Sonar for me is the feeling that Sonar is actually intelligently sorting its social recommendations, and not just giving me random people (I get the unfortunate random person feeling from Banjo, though – which is why I rarely look at it). To continue to improve your sorting and percieved inteligence and trust, Sonar should start incorporating users Klout scores into its sorting. I want to see people around me who are both close and connected to my own social graph, and who are also influential and important in their own social graphs – those are the people with real “value”, and would keep me coming back to Sonar whenever I’m checking in and checking out venues.