Mods are a contentious issue in the FF14 community, being that they're against the terms of service. Just in case, let me caveat my explainer of this delightful mod with the statement that I don't use it, and that I got these screenshots from an unnamed friend.
In a broader sense, I'm generally against mods that impact your gameplay, such as the ones that caused a fuss during the Dragonsong's Reprise (Ultimate) controversy last year. We don't need a World of Warcraft-style arms race between developer and modder.
However, some mods add such great features that I'm shocked they're not a part of the core experience, such as the Orange Guidance Tomestone mod, which is available via the Dalamud plugin.
The Orange Guidance Tomestone brings the charming meme nonsense usually relegated to Twitter and Discord into Eorzea. It works shockingly well, allowing you to see other players' messages, rate them, and design your own.
The mod has a few options for phrases. There's the entire library from Dark Souls, Elden Ring, and Bloodborne, but there's also u31.com เข้าสู่ระบบ a custom pack filled with objects and NPCs from Final Fantasy 14 itself.
Thanks to the current lack of an exploration zone, I've found Final Fantasy 14: Endwalker to be a bit of an isolating experience so far. This mod—if I used it, which I totally don't—patches that hole so nicely that I'm astounded it's not a feature for the base game.
Ultimately, Final Fantasy 14's big draw is a communal, episodic saga that we all take part in. Being able to leave delightful graffiti on the world of Eorzea feels like a logical next step. In Dark Souls, these messages bring vibrancy and gallows humour to a grim world. In Final Fantasy 14, they make an already-vibrant world just that bit brighter.