This thesis describes the project Airwriting and its software architecture. It is a private and mobile messaging service for managing text messages which are explicitly provided with specific attributes.
More than 30 potential attributes are presented such as location of the message, the weather of the location and the current mood of the receiver of messages. A prototyp with a selected subset of these attributes is presented on three different mobile platforms (Android, iPhone, J2ME). More than 65 similar projects are shortly evaluated and compared to Airwriting. The results of a usability study with 20 users are discussed and summarized