1763 Copyright © 2019, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 130 DOI: 10.4018/978-1-5225-7598-6.ch130 ABSTRACT During the past decade, there were rapid developments on the internet, computing technologies, and widespread use of location-aware technologies such as GPS and mobile technology. These developments made it easier for people to communicate and share their opinions, views, knowledge, maps, and much more through software platforms. These technologies have participated in the creation of what is now called Web 2.0. It is a new era of the web where users play an active role in adding contents to the web in a collaborative way, instead of just consuming the web contents. People are sharing social media posts, blog posts, product reviews, ideas, opinions, and much more. Crowdsourcing is a phenomenon that appeared due to the ability of web users to contribute to the web (Web 2.0). This chapter serves as a general overview of crowdsourcing. It investigates various attempts to defning the term, its conceptual models, its benefts and challenges, its applications, and explores some online crowdsourcing systems, software platforms, current and future research avenues. INTRODUCTION During the past decade, there were rapid developments in the Internet, computing technologies, wide- spread and use of location-aware technologies such as GPS and mobile phones. These developments influenced how people communicate and share their opinions, views, knowledge, maps, and many others throughout software platforms. These technologies have participated in the creation of what is now called Web 2.0, which is a new era of web technologies enabling users to play an active role in adding contents to the web in a collaborative way, instead of just consuming the web contents. People are now easily sharing social media posts, blog posts, product reviews, ideas, opinions, maps and others. Crowdsourcing is characterized as a phenomenon that appeared due to enabling web users to contribute to the web. There are many online Crowdsourcing applications such as Amazon Mechanical Turk, Open Street Map, and Yahoo Answers amongst others. Thus, crowdsourcing is a collaborative process which involves four main components (requester, crowd, open call and platform). People might benefit financially or intellectually from participation in crowdsourcing. This chapter serves as a general overview of crowd- sourcing research and envisages future research directions. An Overview of Crowdsourcing Eman Younis Minia University, Egypt