People use social networks (online or offline) for psycho-emotional reasons. (IMHO) Faced with an overwhelming tsunami (per Mark Pesce) of information, many people are using their personal networked space (facebook, myspace, bebo, twitter, etc) to cocoon, to protect themselves from the deluge. They are using RSS feeds and news alerts to avoid getting all the other information. I believe people will get even more choosy about the content they receive. I’m not saying email marketing is facing extinction but it is certainly ailing.
Also, when interactive TV becomes part of our lives (the Federal Government promises 2010, for god’s sake, make it happen!), can you imagine the impact of social networks? People will be able to watch TV in one corner of the screen while commenting on what they’re viewing in their personal networks… Never mind Idol, Dance or Big Brother, think how that will affect an election outcome when people can vote by remote control without getting out of their chair.