As a further sign of the times in the challenging world of print media, the 100-year-old Christian Science Monitor will cease printing in April 2009 and thereafter be available only over the Internet, the first major U.S. periodical to take this step.

In announcing the action, editor John Yemma said having a daily print edition had become “too costly and energy-intensive.” Online journalism, he said, “is more timely and is rapidly expanding its reach, especially among younger readers.” Yemma added that CSM’s bold step “is likely to be watched by others in the news industry as they contemplate similar moves.”

The Chicago Tribune’s Phil Rosenthal describes an “end-of-the-world-as-we-know-it vibe” among those in the news business these days, and says CSM’s decision is “intriguing.”

“It’s also a test case to be watched intently by anyone who enjoys flipping pages, or at least need something for the bottom of their pet’s cage,” he writes.

When asked about whether a New York Times print edition could disappear, publisher Arthur Sulzberger Jr. said a week before CSM’s announcement that “The heart of the answer must be we can’t care.”

Fewer and fewer readers are getting newspapers on their doorsteps or from newsstands, and nostalgia cannot compete with economic reality. “I care very much,” Sulzberger said. “But we must be where people want us for our information. It’s the thought of cannibalizing yourself before somebody else cannibalizes you.”