Sonar, a social discovery service (and TechCrunch Disrupt alumni) which was among the top apps at last year’s SXSW in Austin, is today announcing new investment from  Bing Fund. This angel fund and incubator program from Microsoft was publicly revealed this summer, allowing Microsoft to partner with entrepreneurs, which can then receive subsidies to use Bing APIs in their applications, as well as access the technologies developed by Microsoft Research.

… For background, Sonar’s app uses check-ins on Facebook and Foursquare, plus geo-tagged tweets, to show you lists of nearby people, ranking them first by friends you know, then showing you other relevant people nearby. This type of app works well at crowded events like conferences – or SXSW, for example – but like Highlight, Banjo, INTRO and others, it has yet to become a breakout hit where mainstream users return to launch it daily.

Sonar isn’t disclosing the size of the Bing Fund investment, either, but it did announce the news via Vine.