It's not first. It's the first to implement payments with LN, but direct payments for posts on eocial media have been tried and failed before.

Most famous would probably be Libra by facebook that didn't even make it to launch iirc. Less known. but still applicable would probably be Steemit, which tried a similar concept, except that they created their own shitcoin for that.

And given that LN is a relatively recent thing, It's not thst surprising, that there isn't anyone else doing it yet. (sic!)