摘要：Internet has grown extensively in its availability, connectivity and geographic distribution since 1990s (Weiser,2000, p. 167) and become a part of daily life without being restricted to a specific geography and user group.Correspondingly, the number of internet users has risen dramatically and it continues to rise. The number ofinternet users exceeds 2 billion worldwide (http://www.internetworldstats.com/stats.htm, March 2011) and thisfigure equals to approximately one third of the world population.
