Hearst Corp., one of the largest media conglomerates in the world, says its rolling out an electronic reader for its newspapers and magazines, similar to Amazon's new kindle e-book reader.

The company also said it will hold back from putting all its content online for free as advertising continues to slow.

The e-reader news, first reported by Fortune magazine, will offer content from its 16 daily and 49 weekly newspapers, and its hundreds of magazines. Examples of those include the San Francisco Chronicle, Oprah Winfrey's O, and Cosmopolitan.

It's unclear if the device Hearst has been working on has anything to do with the eReader that Plastic Logic unveiled recently, but its principle seems the same. It's a handheld device used to read digital content, much like the Kindle.

Meanwhile, the amount of print newspaper content Hearst will keep off its free Web sites has yet to be determined, The Wall Street Journal reported Sunday. Cablevision Systems Corp. said last week it plans to turn the free Web site for its Newsday daily into a subscription site.

Exactly how much paid content to hold back from our free sites will be a judgment call made daily by our management, whose mission should be to run the best free Web sites in our markets without compromising our ability to get a fair price from consumers for the expensive, unique reporting and writing that we produce each day, Steven Swartz, Hearst Newspapers president, said in a staff memo obtained by the Journal.

The financial impact of slowing ad sales is unclear because there are no existing comparable models, but many newspapers have seen online advertising shrinking to less than half -- and some far less than that -- of the available ad slots on their Web sites, the Journal said.

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