Alongside Tencent Weibo, Sina Weibo used the double-delimited #HashName# format for hashtags.
Sina Weibo is a Chinese microblogging platform launched by Sina in 2009. Its hashtag syntax differs from the familiar single-opening-hash style used on platforms such as X and Instagram: a topic is enclosed by a hash sign at both ends. This convention helps mark where a hashtag finishes in Chinese text, where words are not normally separated by spaces.
Sina Weibo and Tencent Weibo developed this approach independently of the best-known Twitter convention. The result is easy to confuse with ordinary punctuation, but the closing hash is a defining part of the format. Sina Weibo is also commonly called Weibo, although “Weibo” can refer more broadly to Chinese microblogging services.
The wider hashtag story began with online chat and social-network tagging before becoming strongly associated with Twitter. Chinese-language services adapted the idea to the writing system rather than simply copying English-language spacing rules.