AbstractThis is the age of data revolution. Governments, businesses, and individuals increasingly rely on accurate and timely data in their decision making. New technologies are taking place to increase the amount, quality, speed and usability of data; new tools are being developed for dissemination of data; and new methods are being invented to derive valuable information from raw data. There are however new challenges with respect to how data should be collected, how it should be stored, managed, transferred and ultimately how to make the most out of this ever growing, so called "big data". Governments seek to have tools to collect and meaningfully analyze the data to support their policy decisions; businesses strive to know the facts for their business investments and individuals want to access relevant data anywhere and anytime they need to make decisions. Moreover, developers are extensively using the "big" and "open" public data to create new applications for government agencies, businesses and individuals. Throughout this paper, we will discuss what makes the public data really "open"; why is it crucial for government transparency, citizen engagement and service innovation; what are the steps governments should take to publish their data; and moreover how data openness contributes to mobileGovernment implementations. Among all the other potential outcomes, we highlight Open Government Data's economical and social benefits by unleashing the power of ever growing amount of "big data" in favor of more efficient governments and empowered citizens and businesses. It is highly critical that all the stakeholders realize the benefits and opportunities that OGD brings to the table, and work in collaboration for data openness as well as its efficient use for better public services and innovative service applications for governments, businesses and citizens. Although the discussions about the relevance of data openness in public sector are significantly encouraging, there has not been a single country yet to realize the full potential of government data openness due to certain setbacks. Therefore we will showcase the good practices and steps required to open public data to serve as a guideline to governments. Keywords: open government data, mobileGovernment, innovative public services, efficient government, big data