Netflix (NASDAQ:NFLX) can stream many of the most popular TV shows ever produced. But the streaming catalog still has some glaring holes.

Right now, you go go to the American version of Netflix's streaming video service and enjoy some extremely popular TV shows. Judging by the number of user ratings in the Internet Move Database, Netflix offers seven of the 10 most popular shows ever produced.

In a previous article, I debated why House, M.D., Game of Thrones, and ER weren't available in Netflix streams. Since then, House has in fact joined the Netflix catalog and seems to have earned quite a few viewing hours on the streaming service. Three million Netflix users have offered reviews of House, roughly in line with the ratings volumes of success stories like House of Cards, Mad Men, or Parks and Recreation.

So Netflix is working to fill in the cracks in its content library. That being said, the company still has a long way to go. Here's a look at three hugely popular shows that are not available on Netflix streaming today, including some thoughts on when we might expect them to show up.

Source: Friends, official Facebook pages.

The NBC (NASDAQ:CMCSA) sitcom, which ruled the TV airwaves for 10 years, is the seventh most popular TV show in the IMDB rankings. A veritable star factory, Friends made household names out of Jennifer Aniston, Matthew Perry, and Lisa Kudrow. It finished among Nielsen's (NYSE:NLSN) annual top five viewership rankings in nine of its 10 seasons, was nominated for 62 Primetime Emmy Awards, and is often seen as one of the finest comedies ever made.

Seems like a natural fit for the most popular digital TV service of this day and age, right? But Friends is not, and has never been, available to stream from Netflix.

So what would it take to get Ross assuring everyone that he's fine with Rachel dating Joey, in front of 50 million Netflix viewers?

First of all, a few million Netflix users can actually see the show today.

According to a Reddit discussion, you'll find the first three Friends seasons on Netflix in Norway and Sweden. In Mexico, the first five seasons are available. In Brazil, there'll be seasons 6 through 10. According to international video tracker Moreflix, the show also appears in markets such as Finland, Colombia, and Denmark.

But Friends is absent in the Netherlands, the U.K., and Canada. And above all else, you can't stream it in America.

Mega-hits like Friends often set up their own unique patchworks of broadcast rights, long before newfangled services like Netflix come knocking. In the U.K., the rebroadcast rights belong to Viacom (NASDAQ:VIA) subsidiary Comedy Central. In the U.S., the rights are split between Time Warner (NYSE:TWX.DL) property TBS and Viacom's Nick at Nite.

That split in the domestic market makes everything more complicated. To land distribution rights for Friends, Netflix would have to outwit, outbid, and outlast not one but two rivals. It helps that Warner produced the show and holds most of the cards in any negotiation, but Viacom can throw wrenches in the process at any time.

Netflix does seem to have landed on Warner's white list lately, judging by the recent agreement to stream soon-to-launch Batman prequel series Gotham. But the complex licensing situation for this classic hit show breeds difficult and potentially expensive licensing talks.

In other words, I wouldn't take the the spotty international Netflix coverage as a sign of an impending American launch.

Still waiting. Source: The Simpsons, official Facebook pages.

The Simpsons
OK. How about the longest-running primetime TV series in any category?

The Simpsons is more than just a show -- it's a cultural institution. Seventy-eight Primetime Emmy nominations don't tell the whole story of an icon that introduced many cromulent words into the English dictionary and earned a series of custom USPS postal stamps.

But Netflix doesn't stream The Simpsons anywhere in the world. And this might be a tough nut to crack.

You see, production studio Fox Television is keeping this jewel close to the vest. The show has never aired on an American network not owned by Fox, and the company manages most of the worldwide distribution via in-house properties abroad.

And it gets worse (or better, if you're a fan or investor of Fox). In August, The Simpsons ' domestic syndication rights were passed to recently kick-started cable channel FXX. That's another Fox subsidiary, and it includes an online streaming option. Via an app and website named Simpsons World, due to open its doors in October, fans can enjoy all 522 episodes of seasons 1 through 25.

That's tough cookies for Netflix. Why would Fox allow a rival digital broadcaster to handle this show, when Simpsons World is just getting started?

On the other hand, Simpsons World will require validation by a cable provider, meaning that you can use the app only if FXX is available on your cable dial. Cord cutters need not apply. That wrinkle might be the downfall of Simpsons World, opening the door to a Netflix agreement somewhere in the future.

Just don't hold your breath waiting for The Simpsons in your Netflix streaming queue. It could be bad for your health.

Ready to break out? Source: Seinfeld, official Facebook pages.

Finally, let's take a look at a fantastic show about nothing.

Seinfeld was the first sitcom to command ad rates on par with the Super Bowl. If Friends was a ratings monster, consider that Seinfeld ranked in the top two of Nielsen's year-end listings five years in a row. Sixty-eight Primetime Emmy nominations helped TV Guide crown it the greatest TV show of all time. The show has reportedly collected nearly $3 billion in syndication fees since going off the air in 1998.

And, as with the other greats we already discussed, Seinfeld is not available to Netflix subscribers. Not here, not overseas, nor south of the border. No Seinfeld for you!

However, this show has actually seen some rumblings about Netflix availability.

In July, Jerry Seinfeld held court at Reddit, where he answered fan questions as part of the popular Ask Me Anything series. Netflix came up. And Jerry didn't entirely dismiss the idea.

"Can you please convince [co-creator] Larry [David] to let it happen?" wrote a Reddit reader. "There are so many people who still have not experienced Seinfeld firsthand and having it available through Netflix will surely be the easiest way."

"You are a very smart and progressive person," Seinfeld answered. "These conversations are presently taking place."

That's still far short of an official announcement, and Seinfeld's "conversations" may not lead anywhere. But if you wanted to bet money on which of these three shows is closest to your Netflix queue today, Seinfeld should be the clear favorite.

Anders Bylund owns shares of Netflix. The Motley Fool recommends and owns shares of Apple, Facebook, and Netflix. Try any of our Foolish newsletter services free for 30 days.

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