a.k.a. hashtag diplomacy, social activism
Hashtag activism refers to the use of Twitter's hashtags for Internet activism. More specifically, hashtag activism is the act of fighting for or supporting a cause that people are advocating through social media like Facebook, Twitter, Google+ and other networking websites. This is the kind of activism that does not require any action from the person other than sharing or liking a post or tweeting or retweeting tweets on Twitter. The term gets its name from the liberal use of hashtags (#) that are often used to spread the word about a cause over Twitter.
The oldest mention of the term is fromThe Guardian,
where it was mentioned in context to describe the Occupy Wall Street protests.
NetLingo Classification: Online Jargon