Reply Guy
Pejorative for an X user who reliably replies to (usually large) accounts within minutes of every post, typically with low-substance comments aimed at pulling visibility.
A reply guy is X slang for a user who consistently shows up in the replies of bigger accounts, often within seconds of a tweet going up, with comments designed more to gain visibility than to add to the conversation. The term is mildly to deeply pejorative depending on the speaker.
The pattern is recognizable: someone with a smaller following positions their reply at the top of a high-traffic tweet, posts a generic agreement ("This." "100%." "Truth.") or a glib joke, and harvests likes from people scrolling the replies of the original. Done strategically, this can grow a follower count meaningfully fast.
Reply-guy behavior occupies a contested middle ground. On one hand, replying early to big accounts is one of the most reliable growth tactics on X, and many credible accounts grew this way. On the other hand, it can feel parasitic and erode trust if every reply reads like a setup for a follow.
The healthier version (sometimes called "strategic engagement" or just "thoughtful replying") is to reply early and often, but only on topics where you have something specific to add. Quote the part you're responding to. Disagree with substance. Share a counterexample. The reply guy who eventually has actual takes becomes a respected voice; the one who never does stays a reply guy.
Large accounts vary in how they respond. Some welcome any engagement that boosts their post; others mute or block accounts that reply to every single tweet they ship.