As noted here yesterday, DVD sales are down; in 2009 box office tickets outpaced DVD sales for the first time since 2002. The popularity of Netflix is one of several reasons for the decline in DVD sales.
Netflix and Warner Bros. have announced a deal, first rumored last October, which will prevent Netflix from offering new Warner Bros. releases for rental until the DVDs have been on sale for four weeks.
WB hopes this will boost DVD sales, while the benefits for Netflix are "improved financial terms, higher inventory levels and increased access to content for its online streaming service." Supporting the struggling DVD market will ultimately also benefit Netflix in terms of making sure ample products continue to be produced for Netflix to rent.