The example of Current TV is a great example of a type of self-produced media in which s an alternative source of information and news that has risen to compete, especially within a younger audience, with the larger news corporations. I personally thoroughly enjoy Current for its original and unique content as well as its ability to take on controversial topics while seemingly portraying the "everyman" persona. Current has created a market of trust with its viewers, perhaps because of its tendency to come off as a lower budget, produced "for us, by us" type of programming.
Of course the struggle for power is something that will always be an issue of constant change. The advent of social utilities like Twitter and Facebook are most recent in a long line of seemingly innovative communication technologies and there will be many to come. These types of self communication may be, as Castells points out, not intended for public information (32% of blogs made for public) but it nonetheless becomes part of the sphere of global communication information. Social movements through these new communication realms are now more ubiquitous than ever and, from my end, are a welcome shift from the historical institutional power structures.