Social networking

Social networking has certainly taken off in the last few years and I am sure that many wonder how they managed with out it. It has replaced the art personal interaction such as letter writing, phone calls and meeting people. Where perhaps one once wrote to an individual, one can now write to many and never move from the comfort of a favourite chair. Whilst it is a great way to communicate I cannot help but wonder if something is being lost and if things will eventually turn full circle once the novelty has worn off? Although we can chat away and network for hours, how well do we know these new found 'friends'? Will the professional contacts made make any real difference to one's career? I would be very interested to know if there has been any studies into this area of social networking.