The Open Software movement serves as a landmark and a starting point for many “open-something” initiatives, such as Open Educational Resources (OER) and Massive Online Open Courses (MOOC). However, under a pragmatic point-of-view, many of its basic principles are not considered specially when dealing with the above mentioned initiatives: common, industry-standard OER and MOOC lack a considerable set of really open features in a way that deviate the sense of the “O” letter – for Open – in its acronyms. Considering this, the present paper presents a systematization of these concepts around the general principle of openness. There will be discussed some strengths, challenges, and drawbacks in adopting openness as the key for OER and MOOC for Education in 21st Century.