Here is a Google example from when I lived in China: Google was at the time competing with Baidu over the search image market in China. My home internet was fast and with great quality. Only Google image search results had very often problems loading image previews. Its not that it "didn't work". It just failed "a little", maybe half the images in the results pag didn't load. So Google image search wasn't really blocked. It could have been total coincidence that it was like that for years and only for Google image search. The site that was coincidentally competing over the lead in the Chinese search market against a Chinese company. After some weeks, I started using Baidu image search, even though their result quality was worse. But at least it worked. I am sure many people in China did. That's "competition" in China.