## 1 Introduction  
In the past few years, collaborative mapping projects, with the main goal of collecting and distributing freely available geodata, have attracted significant attention from academia, leading towards their integration into research projects in a semantic and meaningful way. There are a variety of projects available on the Internet on which mostly volunteers share their expertise and information.  
One of the most well-known examples of a User-Generated Content (UGC; [1]) online portal is the free online-encyclopedia Wikipedia. Other projects focus on the collection of a diverse type of data and information specifically containing geographic objects and their corresponding information. Due to the voluntary approach to data collection efforts for this particular type of information, it was initially termed Volunteered Geographic Information (VGI) [2]. In 2007, early questions were raised about \"the phenomenon of VGI, and the use of VGI in doing science\" [3], especially in the area of Geographic Information Science (GIScience). Thus, UGC or VGI have developed into popular interdisciplinary research topics in recent years. Most VGI analyses focus on the OpenStreetMap (OSM) project, which provides a plethora of research questions due to its data diversity. An increasing number of studies in the past investigated data quality indicators, the motivation and activity spectrum of the community that share the information or applications that were developed based on the collected information found in OSM. Although different factors have been analyzed in these prior articles which will be discussed in more detail in the second section of this paper, the analyses usually show a similar pattern: The larger the population in the predefined, analyzed area, the stronger the data quality of the collaboratively collected information in OSM gets. To the best of the authors' knowledge, only minor studies on other countries not located in Europe have been carried out and reported. More importantly, no comparative investigation on OSM data for different selected world regions has been conducted.  
The second major factor for collaborative projects such as OSM, after a well designed project infrastructure, is the worldwide community. The volunteers build the foundation of the project and guarantee the detailed data contributions and temporal accuracy of the data, thus it is important to investigate the different worldwide collaboration efforts. The main objective of this paper is to determine similarities and differences in the pattern of VGI data contributions and user activity spectrums for different worldwide urban areas. We hypothesize that different factors such as contributor concentration, population density and socio-economic parameters such as income can influence the data contributions to OSM. The analysis is conducted for 12 world regions representing at least one urban area for each continent.  
The remainder of the paper is organized as follows: The following section gives a brief overview of the OSM project and prior OSM research. The next section introduces the study areas and applied data preparation steps. The third section presents the results conducted for the selected urban areas between 2005 and 2012. The last two chapters summarize and discuss the achieved outcomes and provide an outlook on potential future research.