Why do some members join groups and wont make a intro? of a small group?

Question

Why do some members join groups and wont make a intro? of a small group?

Answer 1

they're called lurkers, and hard to say why they lurk

Answer 2

Maybe shy.  Many people join groups and never contribute

Answer 3

Sometimes they won't post an intro because they are trying to get familiar with how the group works which can take a few days depending on how busy the group is.