An odd form of this comes with the audience gender for the internet niche fandom of Vocaloid. While in Japan, the voices of the predominantly-young-female character vocal series are often fawned over by boys and men (some of them in their thirties), Vocaloid in general is far more popular with girls and women in America. Alternatively, while the Japanese Vocaloids usually get most of the spotlight with the English Vocaloids used as emergency backup, Big Al, by far the most manly-sounding vocaloid thus far, has gained quite a bit more popularity than you would expect. Another English Vocaloid, Oliver, also has a very large following in Japan compared to most English Vocaloids, and his popularity might even surpass Big-Al.
And in Portugal and Spain, albeit on a cult level.
Maru, the fat (or, if you prefer, "fluffy") cat from Japan who loves boxes is extremely popular in America and the English speaking world. Urlesque voted Maru as the internet's favorite cat, beating out Surprised Kitty and even LOLCats.
For whatever reason, German gamers love to make blind Let's Play videos, a trend which started in the United States. Anglophones (or non-Germanophones at large) trying to find a genuine first-time commentary are often endlessly frustrated by this phenomenon.
Look at the Youtube statistics, Sweden happens to be one of biggest sources of views for Epic Meal Time videos.
The Angry Video Game Nerd is rather popular in Japan. Almost every one of his reviews have been completely subbed into Japanese and can be found on Japanese video sharing sites such as Nico Nico Douga.
In fact, the Critic and the Nerd have had cameos in an actual anime.
As his crossover stuff became subbed the other members of That Guy with the Glasses also started getting Japanese fanbases, notably The Nostalgia Chick, referred to as "Nostal-Ko" (Nostal = an English abreviation as typical in Japan and Ko = The Japanese kanji for child, usually also used to refer to younger women) on nico, Spoony, JewWario (for his Super Robot Wars review) and for some odd reason Doug's brother Rob (who they referred to as Ni-San or Big Brother)
YouTube Poop has a thriving scene in Russia (RYTP), Germany (Youtube Kacke), Finland (SinäTuuba Paska), Brazil (YTPBR), and Latin America (YTPH; Youtube Poop Hispano). It's also been acknowledged – but not as popular – in France (YTPFR; French Youtube Poop), Hungary (Huntube Poop), the Netherlands (Youtube Poep), and Poland (PYTP).
Worth noting that many of the top Finnish YTPers work in English, only venturing into their native language for the lulz.
In fact, in Japan, they have MADs, which are somewhat like YTPs, that then spread to China and Korea.
While Shifty Look is officially owned by Namco Bandai, the webcomics are made by people from other parts of the world to localize Japanese Namco I Ps and cater to English speaking audiences, but the Shifty Look website has gotten so much web traffic from Japan that they decided to also translate the comics to Japanese as well.
Spoony has quite a large following in Finland.
Going by the comments on Nico Nico Douga, React's Lia has some fans in Japan, and some fans in Taiwan as well. She's hardly unpopular in the States or UK, though.
Despite Rémi Gaillard being French he is getting lots more fame in the US than he gets in France. This may perhaps explain why his video's all have English titles and title descriptions despite the fact that his early video's contain French messages (the title descriptions below it are still in French though).
Welcome to Night Vale, an American horror-comedy podcast series has quite a large following in Britain (relatively speaking), much to the surprise of the series' creators. On their first European tour, they sold out three live shows in London and had to do a fourth, selling more tickets than anywhere else they had ever been – even the series' native New York.
An in-universe example in Zhirinovsky's Russian Empire: US President Bob Kerrey has mixed reputation in America. Risking nuclear war with the UIS to prevent them from occupying Kosovo and possibly massacring ethnic Albanians makes him popular in America when the UIS withdraws, but makes him an idol to the Albanians. Hundreds of Albanian children are named after him, one of whom becomes a teen pop sensation for sharing Bob Kerrey's name, and for his hilariously bad music.
Here is a fun little game: Type in the name of a webcomic made in any place outside of the USA that was written in the English language and look at its "audience geography" rating on Alexa. 90% of the time it will have the most popularity in the United States. America Takes Over the World indeed… though it's understandable when one considers that the USA has more native English speakers than every other country combined.note Nearly 300 million, for the record.
Uncyclopedia was started by English speaking people with the English version being started first but now, the Portugese version has more articles than the English version does.
Filipino internet comedy duo, Moymoy Palaboy, who are known for their videos of lip-synching songs had a huge fanbase in Latin America. They even become more famous when their lip-synch video of "Everybody" by the Backstreet Boys with Filipino actor Mark Hieras became a subject of a certain Japanese MMD video with Touhou characters imitating their moves. Apparently, Ryan Seacrest erroneously reported the other way around. Oh and this is before Dub Smash became a hit in the Philippines.