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