Download.com has until now enabled software vendors and authors a free way to promote their latest software and encourage visitors to buy copies.
Cnet's announcement, which it blamed on its high bandwidth costs, has sparked criticism from many developers of free software who simply cannot afford to pay for the service and will therefore be forced to go elsewhere.
But Cnet sees this as more of a benefit than a problem.
"We anticipate a reduced number of less professional products will be listed on Download.com due to this change, which should be a direct benefit for publishers since a reduction in the sheer number of titles should reduce competition," said Robert Borchert, vice president of investor relations at Cnet. "It will also increase the overall value of the download library to our users."
Current publishers who have products listed on the site will not be charged until they update existing titles or add new wares.
The payment scheme will offer the choice of five different payment schemes, from Basic, a $99 (£64) one-off processing fee, to the Gold listing package which provides added benefits such as performance statistics and promotional opportunities and costs a whopping $299 (£192) per month. More information on the packages can be found here.
Despite a recent trend by other sites to charge users for downloading software, Cnet backs its decision to ask the software writers to stump up.
"Download.com has before been free to both software publishers and individuals downloading the titles. This is an initial step to provide low-cost, high-volume marketing opportunities for publishers to reach potential buyers," said Borchert.
"The users already have the opportunity to purchase many of the professional software versions through Download.com," he added.