Open source is a set of principles and practices that promote access to the production and design process for various goods, products, resources and technical conclusions or advice. The term is most commonly applied to the source code of software that is made available to the general public with relaxed or non-existent intellectual property restrictions. This allows users to create user-generated software content through incremental individual effort or through collaboration.
Some consider open source as one of various possible design approaches, while others consider it a critical strategic element of their operations. Before open source became widely adopted, developers and producers used a variety of phrases to describe the concept; the term open source gained popularity with the rise of the Internet and its enabling of diverse production models, communication paths, and interactive communities.[1] Later, open source software became the most prominent face of open source practices.
The open source model of operation can be extended to open source culture in decision making which allows concurrent input of different agendas, approaches and priorities, in contrast with more centralized models of development such as those typically used in commercial companies.[2] “Open source” as applied to culture defines a culture in which collective decisions or fixations are shared during development and made generally available in the public domain– – – as seen with Wikipedia. This collective approach moderates ethical concerns over a “conflict of roles” or conflict of interest. Participants in such a culture are able to modify the collective outcomes and share them with the community.
AYYANAR JEYAM 
It is flexible and Robust