Netflix has begun enforcing limits on multiple video streams as of September 1, Stop the Cap reported today. As of this month, customers' video streams are restricted to the number of DVDs their plan lets them have out at once, though customers may be able to finagle an extra stream.

"One stream at a time" has always been the official policy for Netflix users, but the company only recently began cracking down on those flouting the rule. Now, officially, customers with the streaming-only or one-DVD plan may only watch one stream at a time, two-DVD plans may watch two streams at a time, and so on. Attempting to start more than one stream with the lesser plans will get you a streaming error, saying there's already a stream in progress.

Mashable notes that the limit only appears to apply to movie streams, and was able to stream two TV shows at once but not two movies. In our tests on a two-DVD plan, we could play three TV shows (Heathcliff, Arrested Development, Mad Men) at once, or two shows and a movie; if we tried to add in Anthony Bourdain: No Reservations on a fourth screen, we were shut out, saying we already had "two movies being watched." Five was right out. We also tried to trick Netflix by playing Arrested Development on two screens with two other shows going, with no luck.

Never mind the math, here's the rub: your entire extended family and circle of friends can no longer share one Netflix account, so there will be fewer delightfully odd recommendation juxtapositions like Passion Fish and Dragnet.

Update: Gigaom writes that Netflix has stated any one-stream limits customers have encountered were a glitch. All customers, including those with streaming-only or DVD-only plans, should be able to access at least two streams. We have reached out to Netflix and await their comments for clarification.

Second update: Netflix has confirmed to Ars that the streaming-only plan allows for up to two streams, but no more, and all customers can access as many streams as they are allowed DVDs, plus one.