Imagine what it might have been like to be Dr. Kleenex. You invent a modern miracle, the cheap paper handkerchief, and suddenly you become the person blamed for America’s disposable culture, praised for a more convenient life, or both.

There never was a Dr. Kleenex, though  the product was created by a team of researchers at Kimberly-Clark laboratories in the 1920s. But there is a real Craig in Craigslist, and lately he is looking at life beyond his little list that happens to be the seventh-most-popular Web site in the United States.

It is also a site that is deeply tied up with the fate of newspapers  indeed, many in the newspaper industry blame the site’s founder, Craig Newmark, for the downturn in their classified-advertising business.

An ardently no-frills, ad-free, user-sensitive site, Craigslist has, by the estimate of its chief executive, Jim Buckmaster, generated more than 600 million free classified listings. (Though nearly all listings remain free, Craigslist has added modest fees for job listings and real estate brokers in certain big cities, and from those fees the company generates $80 million to $100 million in annual revenue. It has a staff of 25, including Mr. Newmark.)