Sonar.me founder Brett Martin

“Thousands,” Sonar.me co-founder Brett Martin said via Twitter. “Life is good.” Sonar–a mobile app that shows you how you’re connected to other people in the room–is one of the six finalists for TechCrunch’s Battlefield competition this afternoon, along with fellow New York/Israeli start-up BillGuard, which monitors credit and debit cards for hidden charges, billing errors, forgotten subscriptions and fraud.

There are two finalists from San Francisco (ccLoop and Getaround), one from New York (Sonar), one from New York/Israel (BillGuard), one from just Israel (Doat), and one from New Orleans (InvoiceASAP).

Adrianne Jeffries is the editor of Betabeat. Follow Adrianne on Twitter or via RSS. ajeffries@observer.com