You may have noticed them on Twitter. Many people accidentally follow them, mistaking accounts like @DailyGagaTweets for the real stars. These false accounts are what are known as “stan” accounts.

There’s a point when fandom gives way to something else — something over-the-top. Stan is the term adopted by the Internet for obsessive fans. A portmanteau of “stalker” and “fan,” the term is derived from the Eminem song of the same name. It’s a phrase that often appears online — it’s seen across Twitter or gossipy corners of the Internet, such as on the popular LiveJournal community “Oh No They Didn’t!”

Stans go by many names, but what they all share is a devotion to a specific popstar — Katy Perry has KatyCats, Justin Bieber has Beliebers, Beyoncé has the Beyhive and Lady Gaga has the Little Monsters.

These Twitter users are infamous for their extreme dedication to their chosen pop stars, often attacking strangers who post tweets and articles critical of their favorite artist’s music. This vitriol often takes the form of spam and flames on Twitter. The term stan war has even been adopted to describe the occurrence of rival stans squaring off against each other to debate which artist is better.

Because of this, stans have attracted controversy for their dogma. Many consider them Internet trolls in the vein of YouTube spammers. Some stans even take the stalker etymology from a tongue-in-cheek to an extreme level. Incidents have occurred with stans showing up to pop stars’ private residences, as has happened with Madonna, Taylor Swift and others.

Such stalking has occurred for years,  but with the concept of stans, the Internet has altered fandom. Before social media, superfans had to seek out one another in real life to connect. Now, they are able to bond with the click of a button or the insertion of a hashtag. For better or worse, stan culture is going strong and not showing signs of slowing down.

A version of this article appeared in the Thursday, Dec. 5 print edition. Jake Folsom is music editor. Email him at [email protected].