For odd reasons the BBQ variant of Pringles were left out, when the new XXL's were released in Denmark. This may have been caused by Denmark's own chips KiMs Chips.
For people of the UK, various American food brands. Corn dogs, Taco Bell, Dairy Queen, Wendy's, Arby's, Denny's. We eventually got Subway, which was... "a moderate" success...
Canada too, to a lesser extent. One fun road trip game to play when crossing the Can-US border is to list all the chain-stores/brands not available in Canada as you pass them. There are people who do thriving business smuggling "classic" Americana like Cherry Coke across the border for homesick expats and Canadians with acquired tastes.
Taco Bell has made its way over to the UK. They did try to break into the UK market previously in the early 90s, with a few branches around Greater London, but it proved too unpopular to be profitable. According to That Other Wiki there are five in UK, and one is on an airforce base. Same goes for Wendy's, which was scattered around London in the 1980s.
Kellogg's used to distribute Brown Sugar Cinnamon Pop-Tarts in Canada but stopped many years ago, citing poor sales.
White castle was once available in Malaysia back in the early 90s. Now they're but a distant memory to those who still remember them. Taco Bell, however, is a far more straightforward example of No Export For You- they've never attempted to enter the Malaysian market at all, and the closest restaurant is in Singapore.
You can even get this within the same country. Bojangle's doesn't exist outside a few southeastern states.
The same goes with Muebles Troncoso, a famous Mexican furniture store located in Mexico City and the city of Pachuca, thanks of a famous, long-runner (from about 44 years) child show named En Familia Con Chabelo, since they're their main sponsors. Despise being well-known in all Mexico thanks of four decades of uninterrupted sponsorship, they haven't opened any store outside Mexico City or Pachuca. This also become a source of endless jokes for many Mexicans about how Muebles Troncoso are now filthy rich thanks of that program, but they haven't opened any store outside the capital.
According to the Irish who visited the United States, the Irish LOVE Mountain Dew. Unfortunately for them and the rest of Europe, it's not manufactured there.
Oddly enough it's possible to buy Dr. Pepper and Mountain Dew from Germany. It makes sense though since a large majority of danes prefer to buy cheap food and soda, and the Border Malls (Malls that literally cover a whole town and are near the border between Denmark and Germany) got mostly everything that didn't get an export to Denmark, Sweden, and the likes.
Conversely, our American Cousins have never been able to experience (if that is the correct word) UK grown fast food companies like Wimpy, Spud-U-Like and Nando's.
Despite American outlets only existing in the Washington area, Nando's is quite well-known to American One Direction fans because it is Niall's favorite restaurant.
Hong Kong used to have Domino's, which has been replaced by Pizza Box. No comparison.
Importation of firearms, at least in places where they aren't banned outright, often comes under heavy and somewhat contradictory restrictions. In particular, the importation of pistols into the United States is done on a "points" system that rewards points for things like target sights or all-steel composition, and deducts them for things like small size or caliber. In particular, the .380 caliber Glock 25 cannot be imported into the US (the other Glocks are imported with fragile target sights, which are removed and replaced with the stock sights by the importer), and the Walther PPK has a specific US-only model called the PPK/S, which gains enough points for importation by using a larger Walther PP frame.
Iran has blocked access to any Google service other than Web Search and Gmail. Given the fact that they might copy a nuclear warhead kernel from Google Codes or use Chrome for their devilish affairs, or worse, use Google Earth to choose a nuclear bomb test field, it's a logical thing to do.
An electronic age update on embargoes? No new 24 episodes for you!
The Kinder Surprise Eggs are famous for being banned in the United States, due to a law from the late 1930's that forbid non nutritional content in foods. Slightly averted recently in March 2013 with the release of a similar product called Choco Treasure Eggs, which are made in the USA and has a different design to avoid the similar fate. Unless Kinder Surprise Eggs adapt Choco Treasure's design, the Kinder Surprise Eggs themselves will still be a NEFY in the US.
Most people in the US and in the UK think of Slayers as purely an anime franchise with some manga here and there; only so many recall that it actually began as a series of light novels. Fifteen novels surrounding the main story exist, along with over thirty prequel novels (chronicling the adventures of Lina and Naga) and even a Crossover story. Indeed, Tokyo Pop only licensed the first eight novels of the main series (in which the first two seasons of the anime are based off of), and they are very hard to come by.
Also, only one manga adaptation of the series was officially translated.
The three-volume diaries of Higuchi Ichiyo. This is especially maddening since many commentaries on her work note that the diaries were better than most of her fiction!
Some wholesalers and distributers from the US ban international shipping, mostly due to the African shipping scams that have surfaced.
Oreos are unavailable in Hungary (except in specialty import stores), due to the success of the local Oreo clone called Pilóta. It doesn't help that nowadays both Oreo and Pilóta are made by Kraft.
Oreos are also absent in Egypt, where the local baked-confectionary giant BiscoMisr produces the universally-beloved Borio. We're not joking.
Dippin Dots are a popular form of ice cream that's sold in North America as well as in many Asian countries (such as Japan, Phillipines, Taiwan, etc.) and Australia. Sorry Europe.
Automobiles are a frequent victim of this trope. In the United Kingdom, we don't get 4-cylinder Jaguar models, or the new 2013 Mitsubishi Lancer, and the Chrysler 200 sedan. Even worse... looks like the UK doesn't get the new Ford Focus sedan, or the naturally-aspirated 1.6 petrol models, or even the Toyota Camry. Proof that Britain still gets let down with major international models.
Romanian VW dealers refused to import until 2011 any of the spiced-up versions of the New Beetle - no 1.8T, no 2.0, no 2.3 V5, no 3.2 VR6. Only the smallest engines in the range could be bought, which contributed to the image of a "girl's car" or "overpriced toy".
The US Air Force's F-22. It's illegal to export, though Japan and Australia have asked about buying them.
Irn-Bru is widely available in the UK (it's the best-selling soft drink in Scotland, and the 3rd-best selling in the UK), but it's far more difficult to get hold of in other countries, partially due to having to comply to regulations; the Australian, Canadian and American versions all needed some sort of alterations to conform to health standards, be it the ingredients or the packaging.
Good luck finding Starbucks in Italy: it simply doesn't exist. The reason? According to its president, "Italians don't like plastic cups or the idea of drinking coffee while walking around". He doesn't seem to know that lots of Italians would actually love that.
Fulfilling criteria #3 (a genre with demand), pornography is frequently subject to "no export for you" — sometimes even between different areas of the US — due to wildly varying obscenity laws. Although the Internet has rendered many such restrictions obsolete, as recently as a decade ago it was common for pornographic materials to be restricted to their country of origin, or if distributed subject to editing, censorship or "international" (re: often bowdlerized) versions. Still occurs today, even with mainstream films. For example, the French film "Q" contained unsimulated sex scenes; the US DVD version, titled "Desires" edits all this footage out.