http://www.msnbc.msn.com/id/11262292/
"The little-known practice, called "throttling" by critics, means Netflix customers who pay the same price for the same service are often treated differently, depending on their rental patterns."
"A September 2004 lawsuit cast a spotlight on the throttling issue. The complaint, filed by Frank Chavez on behalf of all Netflix subscribers before Jan. 15, 2005, said the company had developed a sophisticated formula to slow down DVD deliveries to frequent renters and ensure quicker shipments of the most popular movies to its infrequent _ and most profitable _ renters to keep them happy."
I thought there was something wrong with my netflix subscription when I use to send them back rather quickly and would sometimes wait several days before my next movie would get sent out eventhough there is a distribution center in the city where I live.