One of the most interesting analysts of the news business is Alan Mutter, who blogs as the Newsosaur. I’ve used research turned up by Mutter in several of my regular marketing columns for MinnPost.com. His latest post is not completely surprising, given the events of the last few years, but it’s eye-opening nonetheless.

 “The stubborn refusal of ad sales to recover removes any remaining doubt that newspapers are experiencing a secular change that will radically change their businesses forever,” Mutter writes. “A secular change — like, say, the move from kerosene lamps to electric lights — is one that does not reverse itself when the economy improves.”

He’s calling game over. Newspapers are toast.

The U.S. newspaper business had its best year ever in 2005. It’s been downhill ever since. Newspapers have lost more than half their ad revenue in the last five years, as consumers go online to find information that once was available only in print.

Newspaper executives put on a brave face through much of the downturn, insisting that once the economy recovered, so would their ad revenues. But even as the economy continues to struggle, ad sales for all the other media — magazines, radio, TV and the Internet — have turned positive.

Not newspapers. The first two quarters of 2011 brought more bad news, with continuing sales declines — down 7 percent in the first quarter and, anecdotally, continuing their slide in the second quarter.

As a former newspaper reporter and a lifelong newspaper reader, I’m deeply saddened by this state of affairs. But based on the numbers, it’s hard to disagree with Mutter’s conclusion.

Ever since the birth of the Internet, newspaper people have made dark jokes about being in the buggy-whip business. I doubt if any of them are laughing now.