It's anonymous to people outside - but obiously not to members. In addition, people only identify themselves by their first names - so to all intents and purposes, they remain anonymous even to the other individuals in their own group. The Samaritans works on a similar principle - volunteers are known by their first name and a number, and do not disucss, or even acknowledge their membership outside their own branch. Nonsensical plot lines in major BBC medical dramas where a volunteer is keen to blur his professional life with his Samaritan activities gives the organisation a perspective that is untrue, as well as unhelpful.