Sogou Pinyin

By July 2011, Sogou Pinyin had an 83.6% penetration rate with more than 300 million users.

[1] Sogou Pinyin provides features for customizing its dictionary, appearance and function.

Shortly thereafter, a new version of Google Pinyin was released which no longer appeared to be based on Sogou's database.

[6] In 2009, Sogou launched a Bookmarklet named Sogou Cloud Pinyin (搜狗云输入法) that can allow any major browser to input Chinese characters on a webpage without installing any new software or plugins.

It uses JavaScript and Ajax on the browser and apparently cloud computing technology on the servers.