When i was a kid i used to wonder why my grand mom used to be so curious about the postman coming to the house, be it a special occasion from her side or senders. She used to be very quick in terms of responding to her friend/relatives, no matter her friend was in next street or different city. She used to enjoy every bit of 'Catch-up' part in the message and used to discuss it with everyone in the house. Now if you take this time further back you will find the same incidences. Human being has been social animal for ages, call it AD or BC. It is just the mode of communication which is evolving.
It is interesting to see that marketing has pitched in with these evolving modes of communication. Social Media marketing has been quite effective in terms of spreading the word about a new product or getting the end result of a marketing campaign. It has been effective and one of the best way of marketing. The pace at which it is growing makes one feel that there is no tomorrow. Also, with the technology and innovation there seems to be no end to this. So when a few generations back it was word to mouth marketing, it is now wall to wall & tweet to tweet.