Marc Gunther, reviewing Chris Anderson’s The Long Tail in Fortune, deplores “the extinction of mass culture.” Some of us consider it cause for celebration.

Anderson rejoices in the proliferation of niche markets and consumer choice, but Gunther argues that “The advent of 300 channels and the Internet has fragmented audiences – and the explosion of choice has left us poorer.”

I think the explosion of choice has left us poorer in at least two arenas. The first is journalism. (Yes, as a Fortune writer, I’ve got a stake in the health of the mainstream media, which bloggers call the MSM.) The network evening newscasts, big-city newspapers and the national news magazines once had the money, access, skills, commitment and power to deliver lots of original reporting and put important issues on the national agenda. Today, they are all diminished.

To pick a single, timely, example, The Tribune Co. announced just the other day that its newspapers would be closing foreign bureaus in Johannesburg, Moscow, Lebanon and Pakistan. This is happening all over newspaperdom and it happened years ago at the broadcast networks.

Yes, there is more information available to us than ever, but I don’t think we are better informed. Niche media will, inevitably, continue to weaken mass media.

The second arena where we are worse off is politics. This is related to journalism, as the moderate and responsible (okay, bland) voices of the MSM get drowned out by partisan, opinionated cableheads and bloggers.

Yeah, right, I’m really depressed about how responsible (but, unfortunately, lying) voices like Dan Rather’s were drowned out by (fact-checking) Charles Johnson and Powerline.