Every class becomes a small community. Although community is important in all classes I find it particularly important in ongoing classes. The way the community is developed and maintained provides information to incoming students on whether this is the correct class for them.
For most of my life I belonged to a martial arts community where we taught karate, tai chi, and weapons. Most of the students took all three types of classes so the community "feel" wasn't too distinct between them. However the community changed over time. We started out a very "young" dojo. Many of us were in our teens and early twenties. We did a lot of tournaments and were competitive with one another. The community was developed as a family. We were "dojo brothers and sisters." Many of us were actually related (such as me and my sister) and others met and dated and even married through the class. As we aged, so did the new students we attracted. We became less competitive with each other and less concerned with tournaments.
Throughout there was an in-crowd and an out-crowd. I, by virtue of my status (dating and then married to the Sensei) and my rank, was always part of the in-crowd. Out-crowds tended to be transitory. I am not naturally outgoing or social and can't say I did all that much to make new students feel welcome except when teaching them one-on-one. I hope I didn't do anything to make them feel unwelcome but it is quite possible.
Since moving to SouthLite I've joined/tried several ongoing classes. I've tried two karate classes, one I stayed for almost 3 years (b is still there currently but I am not) and the other only for a few months. The dojo where I stayed also had a "family-like" feel as most of the instructors had been studying together for many years. Students come from a range of backgrounds and ages, but karate tends to attract the younger crowd. In fact we would frequently have small children in class and/or mother-daughter students. It took me a long time to feel accepted there but I realized I would never be truly "inside" because I did not come up through the ranks in that style, no less that dojo. Coming up through the ranks is very important in karate. It is a hierarchical system and who you train with matters. This insider/outsider status was not the reason I stopped attending but it didn't help.
More recently I've been taking classes through my new gym. I've tried several yoga classes and one instructor is my favorite. I try to make her class every week. She has many regulars and I've seen several of the regulars in other yoga classes as well. I'm not the type to go up and introduce myself, especially when doing anything physical. Even in my original dojo I was pretty aloof while working out and tended to socialize before and after the class. The yoga regulars are not inviting. They chit-chat before and after class but there is a definite sense of distance between class members. I wonder if it is the nature of yoga, which seems a very solitary practice, or this particular gym? I've even seen people in the class who I know from my university and yet we barely exchange pleasantries.
I've also started taking a tai chi class. I love tai chi and have truly missed it over the years. I'm very happy with the instructor, who teaches at several gyms throughout my city. At my gym we have a very regular group showing up 2-3 times a week. Most are senior citizens. There is a strong sense of community and it is actively upheld. Newbies are welcomed and introduced before the class even begins. There is not a lot of chit chat allowed during class, but when people can get away with it, they ask me detailed questions and are really interested in the answers. They greet and engage each other when in the gym for other reasons. Today two different people told me how glad they are that I've joined the class. Is it the nature of tai chi, which is generally a relaxed and non-competitive art? Does it come from the instructor? (This seems unlikely as he is a very nice man when you speak with him but, like me, gives off true introvert vibes.) Or is it that senior citizens come from a time when being cordial was the norm?