The symbol, #, had certainly been used in various contexts before, but it was now widely spread.

“How do you feel about using # for groups? As in #barcamp, ”Messina wrote in a post on Twitter on August 23, 2007.

Hashtags that aroused commitment

Today, the symbol is widely used in social media to bring people interested in a particular subject together.

The hashtag that has attracted the most engagement on Twitter in Sweden in 2019 is #FridaysForFuture and #klimatstrekk, according to Twitter. Both are about Greta Thunberg and the climate movement she created with her school strike.

#FreeASAP extensively used this summer

After that, #melfest and #mello, which were used extensively during winter and spring in connection with the competitions in the Melodifestivalen.

A third topic that is involved is the deprivation of liberty by hip-hop star Asap Rocky, who was detained in Stockholm for a month after an abuse in late June. #JusticeForRocky, #FreeASAP and #FreeRocky were used extensively during the summer.