According to IMDB:
This is actually quite progressive on the part of Disney, especially following the comments earlier in the year by Iger, who believed the theatre-to-DVD window should close, even suggesting that DVDs be sold in concession stands to grab the market immediately!
Making TV shows available for downloading online does not affect DVD sales of the same shows, according to Disney CFO Tom Staggs. As reported by Home Media Retailing magazine, Staggs told a British investors meeting Tuesday that online sales actually boosted DVD sales of the second season of Lost. "That bolstered our view that we think this wasn't cannibalistic," said Staggs. "In fact, we think there is a good likelihood that this keeps people involved in the shows more deeply." Staggs said that during a two-month trial this summer, visitors to the ABC site downloaded 5.7 million episodes of Desperate Housewives, Grey's Anatomy, and Lost. This fall, four newcomers are being added, including Ugly Betty, Six Degrees, The Knights of Prosperity, and The Nine.