On August 23, 2007, Twitter inaugurated the hashtag, which is used to group messages relating to the same keyword with a single #. Ten years later, the phenomenon has spread to other social media and millions of users worldwide.

It was on the initiative of a Twitter user (@chrismessina) that the hashtag, which has since become one of the most widely known and influential symbols of the internet, was born.

Over the years, numerous hashtags have gone viral on social media, among them #BlackLivesMatter, #IceBucketChallenge and #JeSuisCharlie. Today anyone can create their own hashtags to launch new debates or to group comments on particular subjects. On the Twitter platform, which now has 328 million active users worldwide, the hashtag symbol is currently used 125 million times every day. The managers of the social network have reported that the number of times hashtags are shared has shot up since 2007 when the most widely used hashtag was cited in 9000 tweets. In 2017 some hashtags have already featured in more than 300 million tweets.

Hashtags figure in the daily routine of Twitter users, who post on themes related to the day of the week, like #MondayMotivation, #TuesdayMusic, #ThursdayConfession and the famous #FollowFriday, which has been tweeted more than 500 million times since its creation on January 16, 2009.

For the entire day the dedicated hashtag #Hashtag10 will automatically generate an anniversary emoji.