Twitter uses a different syntax for Chinese characters and orthographies with similar spacing conventions: the hashtag contains unspaced characters, separated from preceding and following text by spaces (e.g.
'我 #爱 你' instead of '我#爱你') or by zero-width non-joiner characters before and after the hashtagged element, to retain a linguistically natural appearance (displaying as unspaced '我#爱你', but with invisible non-joiners delimiting the hashtag).
A hashtag is a type of metadata tag used on social networks such as Twitter and other microblogging services, allowing users to apply dynamic, user-generated tagging that makes it possible for others to easily find messages with a specific theme or content; it allows easy, informal markup of folk taxonomy without need of any formal taxonomy or markup language.
In China, microblogs Sina Weibo and Tencent Weibo use a double-hashtag-delimited #Hash Name# format, since the lack of spacing between Chinese characters necessitates a closing tag.("Pound sign" in the UK means "£"; "#" is called hash, gate, and occasionally octothorpe.) In 1970, for example, the number sign was used to denote immediate address mode in the assembly language of the PDP-11 In the 1986 SGML standard, ISO 8886 (q.v.), # is a reserved name indicator (rni) which precedes keyword syntactic literals, --e.g., the primitive content token #PCDATA, used for parsed character data.The pound sign was adopted for use within IRC networks circa 1988 to label groups and topics.Hashtags intended for discussion of a particular event tend to use an obscure wording to avoid being caught up with generic conversations on similar subjects, such as a cake festival using #cakefestival rather than simply #cake.However, this can also make it difficult for topics to become "trending topics" because people often use different spelling or words to refer to the same topic.