F has 2 meanings
A Twitch stream has accidentally disconnected
Stream's gone; can't see anything
|Twitch||Video game streaming website|
|Streamer||Someone who regularly broadcasts on Twitch.tv|
|Brigading||When one online community harasses another|
|Troll||A person who posts offensive comments|
|Trolling||Posting offensive comments|
|Gamer||A video game player|
In personal ads and forum posts that require a poster to specify their gender, F is short for "female." Usually, a poster's gender is accompanied by their age. For example, a 26-year-old female may write her age and gender as 26F.
In much the same way, M stands for "male" in personal ads and forum posts, and NB stands for "non-binary." People may also use these abbreviations to specify their gender when answering the question "Are you male, female, or other?"
I'm F, 37 years old.
|Enby||A non-binary person|
|M/F||Male or female|
|ASL||Age, sex, location|
|ASLP||Age, sex, location, picture|
|RUMOF||Are you male or female?|
|LGBTQ||Lesbian, Gay, Bisexual, Transgender, and Queer|
In Twitch chat, viewers most often spam F when a stream has accidentally disconnected. This practice began in 2014, after the game Call of Duty: Advanced Warfare included a funeral scene that prompted players to press F to pay their respects to a dead NPC.
Now, online forum and Twitch users often spam F to "pay their respects" to actual deceased people as well as those who have "died" of embarrassment. On Twitch specifically, users also spam F when a streamer's stream accidentally goes dead, in order to pay respect to the "fallen" streamer.