Winkli - Discover who you'll bump into at your Facebook events
uLouder - Modern Craigslist and Nextdoor for urban nomads
Facebook Local - Discover places to go and events happening near you
Explore nearby places for Airbnb - Discover must-see places when browsing Airbnb (Chrome ext)
Remember The Milk - Remember The Milk is a task and time management application for mobile devices.
Whereabouts - Write posts and chat (group or 1-on-1) with people nearby!