Community memory is basically like a big brain that a group of people share! Instead of one person trying to remember everything, everyone in the group can add their own memories and knowledge to keep the community memory strong.
Just like how you might remember something your mom said to you and tell your friend about it later, in a community memory, someone might share a story or a fact they know, and others can remember it too. And just like how you might forget something, sometimes things can get lost in a community memory too.
But when everyone contributes and works together, the community memory can be really useful, like if you want to remember something important about your community, like a special tradition or event, or if you need to find information about something, like how to fix a leaky faucet.