I originally wrote this as an answer to a question on Quora.
“While I know that Google is banned in China and Yahoo Japan uses Google algorithm, I do not know why Google’s market share is so poor in Russia, the US, South Korea. I’m especially interested in bad performance due to linguistic reasons, if they apply. What about the US?”
In Russia, Yandex is dominant. It’s a very good search engine, and is primarily Russian-language focused. It’s been around nearly as long as Google, and people have a certain loyalty to it, especially since it was the first good Russian-language search engine. Russians also don’t tend to be very trusting of U.S. companies.
In Korea, the story is similar. They have good regional homegrown search engines, Naver and Daum, that have been around about as long as Google and that cater specifically to the Korean-language market. There’s no reason to use Google because the local options work quite well.
In these cases it’s a combination of being better in local languages for a long time combined with the tendency to “buy local”. They don’t use Google because they don’t need or want Google.
In the U.S. there are a lot of factors. There have been a lot of good English-language options for a long time, even though many have come and gone. Brand loyalty is a very American thing, even when other brands might do slightly better, and getting a “second opinion” is also pretty ingrained. There are also a lot of people who are uncomfortable with Google’s level of information gathering and profile building (“spying”). This combined with the tens of billions of dollars in the search space leaves plenty of room for competitors, even though it’s very expensive to build a decent search engine and very difficult to monetize one (DuckDuckGo being a good modern example of the difficulty of building one in modern times).
One of the big influences on U.S. market share is the existence of marketing deals. Money changes hands to be featured as the default search engine in browsers like Firefox, Safari, and others. This can move market share by a few percentage points overnight. If you can pay $1 billion for enough traffic to generate $3 billion in ad revenue from the, it’s a great deal. The Apple deals have been very public, but others have been privately arranged.