Limbo is another geo-aware social network that behaves like a mashup of Twitter, Loopt, and Whrrl. One of the app’s most compelling features is its grid-like diagram that visually groups your friends according to what they’re doing (for example, all of your friends that are Out Drinking will be lumped together, even if they aren’t necessarily drinking in the same place). The app accomplishes this feat by forcing users to select from a predefined hierarchical list of activities (while this might sound restrictive, the list is pretty comprehensive). This categorization allows users to see what their friends are up to without having to sift through each of their messages.
You can download the app here for free.