The social networking site Friendster, while long-dead in its birthplace of North America and subject to Anyone Remember Pogs?-style jokes by The Onion, remained theFriending Network in large parts of Asia during the mid-late '00s, The company moved its headquarters to Kuala Lumpur in 2009, and the site's success mostly blocked the rise of MySpace in the Philippines, despite MySpace offering the ability for users to befriend celebrities. While it did cease to be a social network in 2011, this was due to its transformation into a social gaming site instead, which remained popular in the region until they finally pulled the plug in 2015. By the time it was turned off for good, over 90% of the site's traffic came from Asia, particularly Southeast Asian countries like the Philippines, Indonesia, Malaysia, and Singapore.
Google's Orkut social network, out of all the possible countries, saw its greatest popularity in India, Estonia, and especially Brazil. In fact, Orkut became so popular among Brazilians within a year of its launch that many of its American users fled. A few years later, Orkut's headquarters were moved to the Brazilian city of Belo Horizonte. It was one of the most popular websites on the Indian and Brazilian internets, but largely unknown in its country of origin, where its parent company is a household name. Google turned it off in 2014 in order to focus on Google+, though they still maintain an archive.
Another social networking site, Hi5, is based in California yet around 80% of its users live outside the US. For a while it was the most popular social network in Latin America, Portugal, and Thailand (though the rise of Facebook has severely reduced its popularity in some of those countries). Currently, they're trying to follow Friendster and turn the site into a "social gaming" platform.
Fotolog, despite being headquartered in New York City, is extraordinarily popular in Spain and South America, to the point where the Argentinian equivalent of emo/scene fashion was known as the "Flogger". Eventually, though, as Facebook started to gain more acceptance in Argentina, and a few violent episodes covered by the media involving Floggers, starting in March 2009 (end of summer vacations) Flogger fashion started to lay down quietly.
The lesser meme "Leekspin" has become a major Runet (Russian Internet) meme under the name "Yak tsup tsop" in 2006. Subsequently, the song itself ("Ievan Polkka") and its performers (the Finnish band "Loituma") became extremely popular, too, resulting in fansites, cover-versions, ringtones, etc. Orihime Inoue, who was featured in the original flash animation, became something like a symbol of the whole yak-tsup-tsop craze; and (due to most Russians not knowing who Orihime in fact was) was considered a made-up character and nicknamed "Ieva" (after the song's main heroine). There even were some Rule34 pics of "Ieva" (not Orihime!). Orihime is sometimes referred to as the "Loituma Girl" as well.
Similarly, both leekspin and caramelldansen have gone on to be major memes in Japan, with the former leading to Miku Hatsune often being drawn holding a leek, and the latter leading to a wide variety of custom versions of the original caramelldansen gif, which triggered a second, larger wave of popularity in America. In fact, people who didn't know had to be told that the song was Swedish, NOT Japanese.
Caramelldansen videos are now an Ascended Meme due to the original band making an official music video to the Speedycake remix in which they are all depicted as animesque characters doing the very dance that originated from the meme. Warning, Uncanny Valley material in the video.
The instant messaging protocol ICQ, though popular in the late 90s, fell out of favor along with the company that had purchased it, America Online. However, this is not the case Germany, Russia, and the rest of Eastern Europe where it equals instant messaging itself. Indeed, since April 2010, the rights to ICQ have been held by Russian investment group Digital Sky Technologies.
British YouTube user xBextahx somehow became very popular in Japan, where she is known as Beckii Cruel. Her popularity in the UK and US has since gone up due to her collaboration with Area 11 on "Shi no Barado", as well as subsequent appearances with In The Little Wood.
There's also Magibon, a Pennsylvanian twenty-something with a propensity for staring at the camera who's practically become a celebrity in Japan.
When an American father named Allen Rout posted a picture of his newborn baby on his website, he'd never realize years later that it'd blow up into a Memetic Mutation in Japan.
For unclear reasons, LiveJournal is the most popular host for Russian-language bloggers, to the point where the Russian term for blogging is derived from the Russian name of LiveJournal. A Russian company now owns the site, a number of high-profile Russian politicians maintain LJs, Russian authors used LJ to publish excerpts or teasers for their new books, and it's even been theorized that the DDoS attacks on the site in April 2011 were caused by the Russian government in order to silence a critical blogger. LiveJournal is Serious Business in Russia, to the point that so much of its activity is now coming from there that LiveJournal began moving most of its servers from California to Russia in December 2016, and then updated its terms of service to comply with Russian law in April 2017, cementing the service as a wholly Russian entity.
eBay knockoff Yahoo! Auctions quickly faded away everywhere except Japan, where it is by far the most popular site of its kind.
Omegle is infamous for its amount of Indian and Turkish users.
Twitter is very big in Japan, and is popular enough that when Twitter shut down its more popular version 1.0 API in favor of the newer v1.1 API, "API" became a trending topic in Japan, suggesting that the change was rather controversial, while most Western users of Twitter were apathetic at best. It also helps that in Japanese, the same information can be conveyed in less characters than in most Western languages; a 140-character tweet in English may only have 2-3 complete sentences, while a short essay can be written in a 140-character Japanese-language tweet.
Bebo was founded in America, but at its height in the mid-late '00s, it was the social networking site... in the UK and Ireland, where it overtook Myspace in popularity by 2007. Much as Myspace was synonymous with the Emo Teen, Bebo grew associated with the uniquely British "chav" stereotype.
Follow the link to see how a simple iPhone theft can snowball into a Buzzfeed journalist being treated like a major celebrity in a Chinese province.
Yahoo! is still very big in Japan because its information is better localized than Google's is there. It got to the point that, while GeoCities was discontinued in North America in 2009, its Japanese version lingered on for another full decade. Not to mention the aforementioned Auctions and also is a mobile carrier there, which the last one just being brought over recently in the US through Verizon.
Instagram has a noticeably large number of Arabic users.
The VST Instrument Delay Lama by AudioNerdz is very popular and Memetic in Japan, and making covers of songs using the instrument is quite common, and it's also used in the Atelier series for Hagel's different leitmotifs. It helps that's it's essentially a vocal synth with a virtual mascot, much like Vocaloid.
Facebook's popularity is starting to fade away in the First World, as it's starting to lose its "young people club" status due to older people starting to get on it (which is why Zuckerberg made sure to purchase Instagram — this way, younger people would just move from one face of Facebook to another face), as well as due to specialized websites and apps are taking over specific functions of Facebook and doing them better. However, in India and Africa, it is still seen as the pinnacle of modernity and online interaction, and it still has very solid popularity figures in these regions.
In countries such as Mexico, Brazil, Indonesia, or India, SMS messages cost money per sending and their delivery is unreliable. Enter WhatsApp, which came to fill this void by basically acting like internet-based SMS messages. As a result, not a single people from the aforementioned countries uses SMS messages anymore, but a very large part of the country uses WhatsApp. It is starting to spread to countries like UK or Spain, which have tons of expatriates who use WhatsApp to communicate with their peers from abroad.