First

About

First comment (often shorted as “FIRST”) is a phrase used by internet users to mark their initial discovery of a previously uncommented post. In many cases, usage of “FIRST” in a comment thread may trigger a chain reaction of “SECOND,” “THIRRD” and so on and so forth. Frequently practiced across all types of online communities with heavy user traffic & user comment features (ex: YouTube and MySpace), this strange custom of “clocking in” on a comment thread is typically regarded as a troll-like behavior, although it can be used as a playful way to acknowledge the awesomeness of an original post.

Origins

The marking of “first comment” is commonly practiced in a number of different language cultures, so it’s difficult to pinpoint the exact origin of its usage on the web. In a broader sense, the word “first” signifies an air of seniority/legitimacy that no other ordinal numbers can measure up against.

Popular Usage on Youtube

“First comment rants” are often found on youtube, trolls post “first comment” and let the hilarity ensue, here is an example (NSFW):