[url=http://en.m.wikipedia.org/wiki/Hashtag]Hashtags were often used in information technology to highlight a special meaning. In 1970 for example, hashtag had the meaning of immediate in the assembly language of the PDP-11[5] when placed next to a symbol or a number. In 1978, Brian Kernighan and Dennis Ritchie used # in the C programming language for special keywords that had to be processed first by the C preprocessor.[6] Hashtags then appeared and were used within IRC networks to label groups and topics.[7] They are also used to mark individual messages as relevant to a particular group, and to mark individual messages as belonging to a particular topic or "channel". Generally, channels or topics that are available across an entire IRC network are prefixed with a hash symbol # (as opposed to those local to a server, which use an ampersand '&').[citation needed] Hashtags' popularity grew concurrently with the rise and popularity of Twitter. It inspired Chris Messina to propose a similar system to be used on Twitter to tag topics of interest on the microblogging network.[8] He posted the first hashtag on Twitter: “ how do you feel about using # (pound) for groups. As in #barcamp [msg]? ” —Chris Messina, ("factoryjoe"), August 23, 2007[9] Internationally, the hashtag became a practice of writing style for Twitter posts during the 2009–2010 Iranian election protests, as both English and Persian-language hashtags became useful for Twitter users inside and outside of Iran.[citation needed] The first use of the term "hash tag" was in a blog post by Stowe Boyd, "Hash Tags = Twitter Groupings,"[10] on 26 August 2007, according to lexicographer Ben Zimmer, chair of the American Dialect Society's New Words Committee. Beginning July 2, 2009,[citation needed] Twitter began to hyperlink all hashtags in tweets to Twitter search results for the hashtagged word (and for the standard spelling of commonly misspelled words). In 2010, Twitter introduced "Trending Topics" on the Twitter front page, displaying hashtags that are rapidly becoming popular.[/url]