2002: Google

Illustration: Ellis Hamburger

It's the quinessential on-again, off-again relationship:

Analysts believe the first time Google was blocked in the mainland was in 2002.

When the company agreed to China's censorship rules in 2006, a Chinese version was launched but issues quickly emerged between the two players.

Google attempted to work with China to censor certain searches -- such as Tiananment Square or the word "river" to halt searches on former leader Jiang Zemin -- but the company's policy against storing personal data in China restricted Gmail, Blogger and even Picasa from users.

Shortly after Google Plus' launch, rumors instantly circulated that the social media site had been blocked in the mainland.

Penn Olson reports that Google+ is not actually blocked in China but experiencing heavy server issues making it very difficult to use.

In other words, it is censored.