Most online communities these days are web-based, and support editing and deleting community content (among other things). Before web fora there were (and still are) mailing lists, which can also function as communities. Mailing lists, unlike web-based communities, are write-once -- no editing or deleting community-wide. (Of course, individual recipients can do whatever they want with the messages they receive.)
Are questions about the community/people aspects of mailing lists on-topic here?