Limbo is a mobile social network that allows users to chat with each other on their mobile phone, share what they are currently up to, and share their current location with others. The site also has a “shout” feature where entire groups can chat at the same time on their mobile phones. If someone is nearby and getting up to something that is appealing, you can join them and let them know by confirming on your phone. The last component of the solution is the addition of network-wide number games where users can text in various keywords to a short code and if they guess the lowest unique number they win a prize. Some of these games are free while others will sometimes set you back about a buck.