The Comcast systems in Pittsburgh and Denver are running a little experiment: letting people rent films on demand for $4 simultaneously with their release on DVD.

VOD is in 30 million homes, and the sales of DVDs have slowed, so it is hardly surprising that cable companies are taking advantage of their clout. What is new is that movie studios are willing accomplishes. Normally, they protect their 'release windows' timing how to milk each venue for the most it can produce. Normally there is a 30- to 45-day gap between DVD release and on-demand release.

Oh, Blockbuster, where for art thou in this equation? DVD rentals represent the biggest part of their revenue stream and make a good chunk of money for the studios. As a result, you can bet your bottom line that the studios will be measure results carefully to see if Comcast is the new Blockbuster.