This has been around for way longer than tiktok but with ~ instead of @.

I wonder why we left ~ for @.

Maybe become some foreign keyboard layouts don't have the ~ symbol?

The ~ character for home directories was an old convention that dates from the ADM-3A (1976) terminal used by some early Unix users. The keyboard on that terminal happened to have the cursor control word "Home" on the "~" key. This shorthand was adopted by shells like sh/csh and emerged in HTTP urls as /~user/ being the shorthand for a user's personal web page on a site.

Much later in history Twitter popularized the form "@user" to refer to a personal identity. I'm not sure if they invented the usage or not. This is distinct, but probably somehow cognitively related, to the use of "user@host" for email addresses after bang paths fell out of favor.

For reasons I can't quite put my finger on @user seems a much better sigil than ~user to me, so I'm not bothered that it's become popular.

> For reasons I can't quite put my finger on @user seems a much better sigil than ~user to me, so I'm not bothered that it's become popular.

I think this makes sense if you pronounce the action. On Twitter you'd tweet [at] user(s). I think it made even more sense back in the Twitter via SMS where you had to send a message to Twitter's number but direct at a particular user.

It makes sense in a chatroom if you direct a message @someone (at someone), or if you direct a tweet @someone. So I guess the natural progression of that is @someone becoming the identifier.

Twitter was limited to what was easy to enter on a T9 keypad. Of all the available characters, @ was a good one to go with.

Wikipedia claims it was invented as an ad-hoc convention by some Twitter users, and eventually it became so popular Twitter started turning @username into links.

It was, and and the same with ReTweets (RT) and #hashtags, some of us were even there since the SMS days and witnessed that formal adoption