This is my 1st time post on this subject, because frankly I think the whole thing is juvenile. I can't believe it's still being debated after this long.
When I 1st ventured to this board, it took me awhile to figure out if this was an adult board or another for kids. I am amazed at so many people talking about their clique & defending their right to have one. I'm 38. That makes me about 20 yrs. too old for a clique. Comparing a message board to real life is well silly. If you're with a group of friends & bump into someone who wants to chat, are you going to ignore them. If you're out of high school, I sure hope not.
Noone should need to be invited to join in a thread. IMHO, if the mods see cliques

forming, they should put a stop to them immediately. They reflect negatively on the entire board. Many people on the other boards don't utilize this one because of the groups. It's normal for people to hit it off & become friends. It's not normal for them to acknowledge that they've formed cliques & see nothing wrong with adults acting that way.
When I 1st encountered the inside jokes & hijacking of threads, I assumed it was older teens having fun. I just smiled & looked over it. When I realized that it was mostly people out of their teens, I was bewildered. It's not hard to have fun & behave as an adult at the same time.
Now, for the reason I finally decided to join this discussion. I have seen churches destroyed because of so called cliques. I wouldn't want to be one of those responsible for a split. Forming cliques in church isn't normal. It's destructive. FWIW, having special friends from Sunday school isn't a clique. Having a group of friends that do almost everything together, & rarely including the general population of the church is. A church is a body of people gathered together to worship the Lord. Nowhere have I ever read that a church is a bunch of small groups formed from 1 large group gathered to worship the Lord.
I won't say I hope I don't get flamed for this. Again, I think flaming is immature in the least. We do need to look at how old we actually are & behave in that way. If you want to have personal banter, & exchange inside jokes, do the polite thing & use a PM to do that.