This is the 4575th most frequent Korean word.
가입을
"가입을" means "subscription" or "membership."
In this context, '가입을' indicates the consideration of joining an online forum.
포럼에 가입을 고민하고 있다.
I am considering joining a forum.
In this sentence, '가입을' refers to the action of registering or joining the club.
나는 새로운 동호회에 가입을 신청했다.
I applied for membership in a new club.
Here, '가입을' is used to describe the act of signing up for an insurance plan.