Social campaigns have begun to be titled in a hashtag form. The
International Telecommunication Union (ITU) approved in November 1988 a recommendation that put the hash sign on the right side of the 0 in the button arrangement for push buttons on telephones. This same arrangement is still used today in most software phones (see Android dialer for example). The ITU recommendation had two design options for the hash: a European version where the hash sign was built with a 90-degree angle and a North American version with an 80-degree angle. The North American version seems to have prevailed as most hash signs in Europe now follow the 80 degree inclination. The
pound sign (not to confused with the
pound currency sign) was adopted for use within
IRC networks to label groups and topics. 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). HTML has used # as a
fragment identifier from the very start of the World-Wide Web (). The use of the pound sign in
IRC inspired Chris Messina to propose a similar system to be used on Twitter to tag topics of interest on the microblogging network. He posted the first hashtag on Twitter. Messina's suggestion to use the hashtag was initially not adopted by Twitter, but the practice took off after hashtags were widely used in tweets relating to the
2007 San Diego forest fires in Southern California. According to Messina, he suggested use of the hashtag to make it easy for "lay" users to search for content and find specific relevant updates; they were for people who do not have the technological knowledge to navigate the site. Therefore, the hashtag "was created organically by Twitter users as a way to categorize messages." Today they are for anyone, either with or without technical knowledge, to easily impose enough annotation to be useful without needing a more formal system or adhering to many technical details. Internationally, the hashtag became a practice of writing style for Twitter posts during the
2009–2010 Iranian election protests; Twitter users inside and outside Iran used both English- and
Persian-language hashtags in communications during the events. The first published use of the term "hash tag" was in a blog post by Stowe Boyd, "Hash Tags = Twitter Groupings," on August 26, 2007, according to lexicographer
Ben Zimmer, chair of the
American Dialect Society's New Words Committee. Beginning July 2, 2009, 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. Twitter has an algorithm to tackle attempts to
spam the trending list and ensure that hashtags trend naturally. Although the hashtag started out most popularly on Twitter as the main social media platform for this use, the use has extended to other social media sites including Instagram, Facebook, Flickr, Tumblr, and Google+. ==Press==