Explore:  Browse stories from your neighborhood using a map.

Find out what’s important: Upvoting brings the important stories to the top.

Inform others:  Share what’s going on with your entire community, not just your social network

Be alerted:  Automatically receive community advisories.

Discuss: Have community-wide discussions about the events you care about.

Tumblr : http://www.tumblr.com/blog/geosocial-io