If everyone has a voice, that probably will dilute the impact of the media. However, that voice will not only be by the rich and powerful anymore, and believe me, this is something the ones in power fear, just look at the RIAA or Hollywood *****ing about people downloading movies and music or the production companies crying about TV torrents.
Moving away from the aristocracy that is the media to something democratic is a good thing though. Of course you'll have to filter out the crap, but that's just a small price for communication freedom that you will ultimately enjoy from this new model.
The flash says the exact opposite will happen, and what it looks like we're headed for: a mega media superconglomerate will control everything, and that is as scary or more than the deadliest of weapons. Information really is the most powerful weapon of all. If you control information, you control everything. You could say 2+2=5 if you wanted to, and 2+2 would = 5. Whoever controls the media, controls the world.
If we're not vigilant, it will happen. It's everyone's duty to ensure it doesn't.