While Black Friday will hopefully mean big sales for retailers all over the country, retailers are opening their doors on Thanksgiving for a smaller-scale "Black Thursday."Retailer Sears has never been open on Thanksgiving Day in its long history, but this year, Sears stores will be open this Thursday."More values, an extra day to shop," said Fay Kliner, assistant manager of the Sears store in Carmel Mountain Ranch.To lure people in, Sears is discounting certain items such as TVs, Christmas trees, tools and sweaters on Thursday only.K-Mart, which is owned by Sears, has been open on Thanksgiving for 19 years."We've been very busy at the K-Marts," said Kliner.Shopper Janis Warner wasn't sure about the Thanksgiving Day plans and told 10News, "I kind of feel sorry for the people who have to work on Thanksgiving. I don't think I'm going to be here [shopping] on Thanksgiving."Sears will only be open from 7 a.m. to noon, and store management says the employees who work that day will have volunteered to do so.The main question for retailers open on Thanksgiving is: how successful will Black Thursday be?"They're breaking with tradition to try and create some customer preference and to shop a day earlier," said San Diego State University marketing professor Michael Capone.Capone and his students recently completed a study involving 400 local retailers, and he concluded that success is about more than prices and hours. He said stores need to focus on service."The promise of a discount might drive traffic," he said. "But if that traffic is not welcomed and you're not getting a delightful service experience, that traffic won't convert into revenue."Capone said if consumers don't get service, they might not buy that day and they might not be back.Sears is not the only major retailer to be open on Thanksgiving. Wal-Mart will also be open this Thursday.