Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
Foursquare City Guide - Foursquare City Guide is a Free to use mobile application that will lead you to the perfect spot anytime anywhere around the world.
Groups.io - Email and web based discussion group software, includes archiving, emails, wiki, polls, file...
Sygic Maps - The world's first online maps designed for travelers
Gaggle Mail - Gaggle Mail is a simple and easy to use email list manager.
Flamyngo - Create a city guide with help of your friends.