I think there's a difference between good ones and band ones in this category. The good ones take all voices from all peoples and their communities from all round the world because they have serious issues but not been heard well enough. Here's one:
http://www.indymedia.org/en/index.shtml
The Indy Media Center has been around for a while providing the information that matters to us. It's grassroots and based on activism, so the stuff there is not well organized, but you can get what you need to be aware of.
Meanwhile the bad ones are just part of the exploitatons conducted by the corporate media today. They are lazy and they want some non-journalist people to feed them news stories at no cost. CNN, for instance, without any question does that.
Also, there are a number of websites that claim as "citizen journalism" and run news-like stories, but you examine them a bit critically, they are just some free ad space to be filled in, so they basically ask freebees to sumbit their writings, again at no cost or with a very minimum pay.