Netflix (NASDAQ:NFLX) streams many of the most popular TV shows ever produced, and some the best. But the digital video veteran's streaming catalog still has some outrageous holes, leaving viewers craving shows that just aren't there.

Right now, you can 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 on the Internet Move Database, Netflix offers seven of the 10 most popular shows ever produced.

In previous articles, I've discussed why shows such as Game of Thrones, Friends, The Simpsons, and ER weren't available in Netflix streams. In one case, I pondered House's absence, only to see the show appear on Netflix six months later. 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 huge hits that turned the TV world upside down but are not available on Netflix streaming today. I'll include some thoughts on whether we might expect them to show up on Netflix -- and if so, when.

A father and daughter watching TV on the couch with popcorn

Image source: Getty Images.

The Big Bang Theory
This smart sitcom is one of the three missing titles from's top-10 list of the most popular TV shows ever.

The show explores themes such as relationships, linguistics, role-playing games, and quantum physics. It's loaded with catchphrases, packed with more jokes per minute than any other sitcom today, and shot in the intimate multicamera format that made Seinfeld and Friends sing -- at a time when the more deliberate single-camera format rules the roost.

And audiences are lapping it all up. The Big Bang Theory routinely crushes anything not named "football" in Nielsen's weekly ratings. The show is doing well in syndication, sells millions of DVD and Blu-ray season collections, and has won seven Emmy awards on 33 nominations.

Even better, Netflix has a good working relationship with some of the forces behind The Big Bang Theory. Executive Producer Bill Prady held the same title for Gilmore Girls, which premiered on Netflix last week. Time Warner (NYSE:TWX.DL) subsidiary Warner Bros. Television produced both shows, alongside Netflix streaming titles like Arrow, Gossip Girl, and The West Wing.

Yet The Big Bang Theory is nowhere to be found in the Netflix streaming catalog. What gives?

Actually, Netflix does stream this massive hit show -- but you'll need a plane ticket first. Independent reports show The Big Bang Theory is available to stream in all of Netflix's latest European expansion territories, including Germany, France, and Switzerland. These streaming licenses are locked into specific territories, so Americans can't enjoy Sheldon's brainy antics regardless of the show's French status.

It's possible Warner Bros. Television only wanted to make a deal for Europe, where this show isn't exploited anywhere near as intensely as the studio markets it in America. But you never know.

Keep in mind that House showed up on Netflix in Latin America before jumping to U.S. screens. It's always a good sign when the two parties sit down for negotiations, even if it starts with a foreign agreement.

That's why I wouldn't be shocked to see The Big Bang Theory in my U.S. Netflix queue someday soon. The only thing holding this show back is the fact that it's still broadcasting new episodes with a tasty side dish of older-season syndication. Warner might decide it's best not to cannibalize these cash cows yet.

So I'm not holding my breath exactly, but I'm reserving a special "Bazinga!" just in case Sheldon and the gang ever show up on Netflix streaming.

It can't be impossible.

South Park
Here's a bit of a special case. The third-longest-running animated series in American TV history, another Emmy-winning (and Oscar-nominated) critical hit, and a cultural touchstone with international pull has already made the rounds on Netflix -- and is not likely to come back anytime soon.

Yes, South Park used to be available for Netflix streaming. Not just the Bigger, Longer, and Uncut movie, but the entire series. The often raunchy antics of Cartman and Kyle disappeared in spring 2013, and haven't been seen since.

Comedy Central owner Viacom (NASDAQ:VIAB) brought South Park to Netflix in the early days of streaming services. Alongside other Viacom properties including SpongeBob SquarePants and iCarly, South Park helped Netflix build interest in its then-budding online viewing alternative back when the DVD service still ruled the roost.

In 2013, Netflix and Viacom couldn't come to terms over a fresh license deal. As a result, Hulu now has the exclusive rights to the program.

So South Park is out of Netflix's reach for now. Amazon has the rights locked up in a multiyear deal. The exact terms of that contract are not known, but it's fair to assume Amazon holds these rights until at least 2016. Netflix might bid again when the Amazon deal expires, but the winner of that future duel is up in the air.

In the meantime, South Park fans can grab an Amazon Prime membership -- or take a trip to enjoy the Netflix version in places such as Mexico, Brazil, and Ireland.

Let's end this exploration with a new kid on the block.

Based on a series of Diana Gabaldon novels and turned into a Starz (NASDAQ:STRZA) series, Outlander brings an epic heart-thumper feel to the Scottish highlands. It's Downton Abbey in kilts; it's Game of Thrones in a white dress. The show is still too new to have earned any awards, and Starz offers a smaller platform than the mass-market soapboxes from which Thrones and Abbey shout their stardom.

But Outlander is already a critical hit, and was renewed for a second season less than a week after the series premiere. That showing was Starz's most successful series premiere ever, counting all the multiple delivery methods available to the network's viewers. Outlander is also a big hit on social media, as fans can't stop tweeting about it.

Netflix has a history of snagging streaming rights for new shows, with the caveat that the service has to wait until the end of the season or even longer before debuting the digital goods. So what's stopping Netflix from buying the rights to this quick winner?

Several things, actually.

These two companies have a history, too -- but it's none of the happy cooperation stuff you saw with Time Warner. A license to restream the Starz catalog helped put Netflix streaming on the map, but the two parted ways on harsh terms when Starz started to feel used.

When Starz's studio licenses started expiring, Netflix stole one important contract. Fighting for its very life, Starz likely overpaid for another crucial agreement.

So there's some bad blood between these companies, which helps explain why Netflix streaming doesn't offer any Starz original shows today. Even worse, Starz runs its own streaming service under the Starz Play moniker.

The two companies don't get along, Outlander might be Starz's first blockbuster in the Game of Thrones mold, and we're even looking at two competing streaming services.

Sorry, but you shouldn't expect Outlander to stream on Netflix, with the possible exception of some foreign markets where Starz itself doesn't have any other monetizing options. The deck is simply stacked against it.

Editor's note: The article originally said that's Prime Video Service had the rights to South Park.