More and more technology-savvy educators and educational technologists are going crazy about the use of web 2.0 tools like blogs, social networks (some even go as far as suggesting facebook) and other types of apps like Wikis for learning or in education. Many even go as far as suggesting that these are the modern tools to be used at all cost for all educational systems and processes for learning to occur. In other contexts, some would stress for meaningful learning to occur, as if there are some learning which can be 'meaningless'.
A blog for instance is no different to an online forum in terms of the software and its technological design. A post in a blog can be seen as a new discussion in a forum and each comment of a blog can be seen as a reply to the forum post and these become discussion threads.
Web 2.0 is essentially a concept where users of the web can also contribute to populating the web with articles, news, views and opinions. Facebook can be seen as web 2.0 tool because anyone having a profile there can post 'content' to his profile and others who have access to this profile can post comments on that person's wall. A social network is not necessarily a place where educational type of learning will take place most of the time although it can contain info related to an educational type of learning in which one or more persons in that network of friends are part of. It can contain a simple information on the date of a class test, or the tips provided by a lecturer for the exams. But these are not necessarily related to the core learning process. Same as this message can be used to communicate on facebook, twitter offers a more less same service (specialised as facebook is more general) for that type of activity.
A classroom whether physical or online where participants can be with each other and communicate to each other is already a social network. It does not necessarily mean that it will expand. Therefore using a social network software to create a social network for a particular classroom is a bit of an oxymoron. But the use of a particular web 2.0 tool to promote say critical thinking for a particular learning activity can be a useful idea where learning of some sort will take place.
On the other hand the use of a social network approach to extend the network of one classroom of a particular course at a particular level to connect with peers of similar characteristics across a geographical region can contribute to some extent in the educational process. But it depends on what the network talks about, what they share and what they are doing in that network to shape learning. How much learning goes on the social networks of facebook users? May be all sorts of informal learning or some news or just enough to create a revolution to topple governments, yes indeed it may have broader social effects, but not necessarily related to the more specific issue of learning within a predefined formal educational context, where learning outcomes and assessment structures and learning goals are well defined...........