That crunching sound you're hearing in the distance is the sound of the information gravy train grinding to halt, or at least slowing down.

In a move that sent the blogosphere into shrieks of anger yesterday, the venerable Associated Press announced its intention to challenge the posting of its copyrighted material on blogs and Web sites.

While the A.P. backed off its strong words after a firestorm erupted in the blogosphere, it stuck by its pledge to challenge what it believes is the unfair use of its content on the Internet.

In a story reported by The New York Times, the wire service announced that it will "for the first time, attempt to define clear standards as to how much of its articles and broadcasts bloggers and Web sites and excerpt without infringing on the A.P.'s copyright."

This has enormous implications for Web publishing industry. For years, bloggers and small Web publishers have freely used copyrighted material from the A.P., The New York Times, and every other news organization without fear of legal action.

It is not much of a stretch to say that thousands of bloggers---including PR Junkie--feast off the Internet's seemingly endless supply of news.

The firestorm began last week when the wire service fired off a letter to the Drudge Retort, a left-leaning parody of the more famous Drudge Report, demanding that it take down seven posts carrying quotations from its work. The excerpts ranged from 39 to 79 words.

After bloggers screamed in protest, posting dozens of commentaries attacking A.P., the wire service backed off, saying it would regroup to fight the battle another day with a more well defined policy.

“Cutting and pasting a lot of content into a blog is not what we want to see,” Jim Kennedy, vice president and strategy director of The A.P. explained in an interview. “It is more consistent with the spirit of the Internet to link to content so people can read the whole thing in context.”

You can bet that the A.P. is silently being cheered on by the 1,500 newspapers that make up the news cooperative. Indeed, one wonders why it took the wire service so long to challenge the free use of its content.

Free information has been the oxygen supply allowing low-cost web sites to exist. Without it, bloggers would have far less material to publish and comment upon.

Some news sites in the PR industry rely almost entirely on mainstream news organizations for their own news bulletins. Bulldog Reporter and its Daily Dog is a case in point. Every morning, The Daily Dog is sent to thousands of readers hungry for news on the PR and media relations industry. But much of the content in the Daily Dog actually comes from a technique known as "covering the coverage." Writers simply paraphrase or summarize mainstream press reports, being careful to attribute their information to the AP or The Wall Street Journal. The AP wants to challenge that practice for obvious reasons: These organizations are making money off their content.

Web site publishers argue that their use of mainstream news sources falls into the doctrine of "fair use," an age-old legal principle that allows publishers to excerpt small passages of copyrighted material to make an argument. The classic example of fair use cited by most lawyers is the book reviewer who quotes from a novel he or she is reviewing to give readers a sense of the work.

Whether the fair use doctrine will shield bloggers and small web publishers from challenges by the A.P. will be decided if and when a case goes to court.

In the meantime, bloggers are right to worry about their information gravy train toppling over.