Blockbuster Video stores around the country have started selling previously viewed DVDs - a move with long range ramifications for the sell-through DVD business. Several store employees said the decision to sell used DVDs was made by Blockbuster Inc.ís corporate headquarters within the past two months. E-mails from the corporate office determine which titles will be placed on the previously viewed shelf, one California store manager said.A spokeswoman for Blockbuster acknowledged the companyís entry into the used-DVD business, but declined to discuss specifics.""How we structure the business model for previously viewed DVDs, that is something we consider proprietary,"" says Blockbusterís Liz Greene.Not all of Blockbusterís 4,000-plus North American outlets sell used DVDs.A poll of 35 Blockbuster stores in California, New York, Connecticut, Vermont, North Dakota, Illinois, Texas and Wisconsin found various levels of involvement, with more than 30 percent actively selling titles. Stores in cities such as Fullerton, California; Lake Zurich, Illinois; and Dallas, Texas all reported that they started selling used DVDs within the last couple of months.A clerk in a Vernon Hills, Illinois, Blockbuster said the store did not carry used DVDs now, but expected to start soon. A store employee in a Dallas outlet said that by March 17, more than 100 used DVDs should be for sale.Prices were consistently between $14.99 and $19.99.At a store in New Milford, Connecticut, ""The Blair Witch Project"" and ""The Prince Of Egypt"" were featured for less than $20, while a store in Illinois was selling catalog titles like ""The Exorcist"" and ""An American Werewolf In London"" for $14.99 each. A store in Orange, California, featured ""The Truman Show"" for $14.99 and ""A Bugs Life"" for $19.99. Regardless of the price, store employees contacted said the previously viewed DVDs donít stay on the shelves very long.Several brick-and-mortar retailers and e-commerce operations have already expressed interest in developing the market.Tower Records/Video has been selling previously viewed DVDs for six months. ""Itís a good way to keep your inventory clean,"" says Tower Vice President of Video Sales John Trasher.Tower stores sell used DVDs for $14.99 to $19.99, he says.