Sufficient information on public transport especially in terms of unpredictable events within the public transport system is hardly feasible with current mobility information systems. Due to high costs and lack of reliability of current methods of data collection an increased need for alternative methods to generate travel information is given. Status messages on social media like Facebook and Twitter are increasing across smartphone users of all milieus. These status messages could contain factual information about public transportation conditions or personal sentiments. By the public release of this kind of information, other public transport users may benefit in terms of a higher amount of real-time information and event detection. The use of social media as mobility information system is comparable with the process of crowdsourcing driven by social sensors. Compared to other mobility information systems, social media provides high valuable first-hand and real-time information on public transport. Furthermore this social sensor data may also be used by service providers for supplementing data on public transport generated by physical sensors.