The research deals with the analysis of efficiency of the process of teaching and learning with use of the social dimension of Web 2.0 within the English for Specific Purposes course in pre-school and primary teacher education that would help students to become more cognizant and more responsive to the emerging needs of the market for educational services and to promote their use of the social dimension of Web 2.0. The analysis involves a process of analyzing the meaning of the key concepts "social dimension of Web 2.0", "teaching and learning" and "peer-learning". Moreover, the study demonstrates how the key concepts are related to the idea of "efficiency". The paper introduces the study conducted in Latvia in 2008-2009. The conducted explorative research has been used. The sample involved 47 pre-school and primary student teachers. Descriptive statistics was implemented for primary data analysis. The findings of the research allow drawing conclusions on efficiency of the process of teaching and learning with use of the social dimension of Web 2.0. Directions of further research on the development of student's personal experience in use of the social dimension of Web 2.0 as a condition for creation of new knowledge are elaborated. (Contains 1 table and 6 figures.)