This is a beta version for the Instant Communities application, you can try with different servers (dev, test and beta server) for joining different "communities" and posting your comments and ideas.
Please, before trying to post anything log in with your facebook account in the main page of the application. Then you can post your comments, questions and put something interesting that is in your device.
Before giving bad comments, please keep in mind that is a beta version and has for sure some bugs. Report them so they will be fixed ASAP.