Geo-based social apps have been used in news gathering for a few years now.  For example Foursquare’s “mayors” have been tapped for expertise on a particular location when it’s touched by breaking news.  Gowalla “trips” created by the Austin American-Statesman got some buzz as an example of how a news organization could use these services to provide virtual tours of of local landmarks or other consumer-oriented content.

Now, there’s Highlight.  Touted by USA Today as the most talked-about app at the South by Southwest (SWSX) conference, the app seems to take location-based social media a step further.

Simply put, the iPhone app lets you know when you’re near someone with even the remotest social-media connection to you, and you get plenty of notifications to remind you.

Thinking about  news gathering, it seems possible that this app could make it easier for reporters to find known sources in the chaos of a major breaking news story.  If you’re connected to a local teacher on  Facebook, the app might alert you to the fact that he is just a few feet away when you arrive on the scene of the school lockdown.

Of course, this once again raises the issue of whether journalists should be connected to sources on social media, but it may be getting to the point that you can’t afford not to figure out how to interact with news makers in the social media space.