Most branded community managers would probably have removed many of these off-topic discussions.
But Avon didn’t, that’s why their community is thriving.
Members bond beyond their interest in the topic. They visit regularly to know more about about each other's lives, and share the latest events in their lives.
They're not information-seekers (which most branded communities attract) they're people that want to bond.
If you only allow people to exchange information, your members wont bond with each other. They will only visit the community when they need information (or want to share information). That wont be very often.
However, we have an ever-present need to bond. We want to make genuine human connections all the time. It's what we do when we're not working. The communities where members tend to visit every day are those that feature a high number of bonding conversations and a limited number of branded conversations.
Too many community managers push for branded conversations. They believe their members should be exchanging information about the brand (or topics closely related to the brand). By heavily restricting the types of discussions you allow, you’re crippling the development of your community.