We use TASS, and the Parent Lounge includes an opt-in Parent Directory. Parents can only view the details of other parents from their year group who have chosen to publish their details. They also choose what information to publish – just email or phone for example. We do have some complicated families, so allowing them to decide what will and won’t be published, has been very handy.
We know that there are parent-run Facebook groups, but we do not endorse or participate in those groups, as unfortunately, there have been issues in the past.
However, at my last school, I set up the Facebook groups (organised by graduating year), and parents were generally positive, and used them appropriately. We seldom had to deal with dramas. We did also appoint a moderator from each year group to assist, and part of their role was to ensure that the parents who did not have a Facebook account were still kept in the loop. We did remove parents from groups when their children left the school. It was largely parents reminding other parents of events (and even homework!), lost property, organising the occasional group event, and the P&F could put the call out for volunteers via the moderators or the school.