It depends who you ask. Like any people who share a common trait, you try to find other people who share the same trait – or same-ish, in the case of paganism.
Most towns and cities will have a group of pagans meeting regularly somewhere, they may meet in a public place, such as a pub, and advertise their meetings, or moots to all. These are simply called ‘open meetings’ and may be more of a social with a pagan flavoured discussion, short workshop or lecture in there somewhere. Open meetings may also include ritual and ceremony done in public places, such as the open ritual at our Summer Camp. Because it’s done in the middle of a camp site, we open watching the ritual to all, including members of the public who may also be sharing the site at the same time as us.
Opposite to this are ‘closed groups’ usually smaller working or ritual groups which are by invite only. Just because you belong to an open group doesn’t mean you can’t belong to a closed one, and likewise belonging to one closed one, in principal, doesn’t exclude you from belonging to another. I say in principal, because some closed groups (especially in witchcraft or wicca) are called covens, are traditionally groups of thirteen people, and membership of a coven may preclude belonging to another. If you are invited to join a closed group, talk to the person who has issued the invitation and ask about any ground rules, and to be given some time to think about it first. There should be no pressure to accept an invitation straight away, likewise there should be no pressure to stay if you do accept. If there is, well, then perhaps the group isn’t as balanced as you might like. Closed groups often meet at an individuals house, and so the homeowner may prefer to know the people he or she is inviting into his or her home, rather than throwing it open to strangers and members of the public.
The purpose of the group may also be the reason that it is closed, ceremonies, rituals or the celebration of the sabbats can be a deeply profound experience, often best shared with a few familiar people. A closed group may be formed to study a particular aspect, as a healing circle or to learn from one particular member. As the knowledge and experience increases with each meeting, building on the last, a commitment is needed from each member to attend, so that the learning progresses and time is not wasted in repeating the lessons previously learned.
Witchcraft isn’t all about secrecy, but some teaching and learning is done in closed groups. Most pagans will be quite open and happy to discuss their particular beliefs with you until long past the cows return home 🙂