2种解释都有吧.
这是个英语论坛,里面讨论了这个.有点英语基础你会看懂的.
有个人给的in This is an expression related to "the in-crowd." It means there is a clique,an exclusive group of people that has social power,esteem,respect,money,the latest fashions,expensive things,etc.Someone who wants to be "in." wants to be part of this group.”
意思就是成为组织的一员这个意思