I'm curious as to why more brands don't just use 'groups' instead? I'm in a couple of groups that are basically companies and I get all their status updates as

I'm curious as to why more brands don't just use 'groups' instead? I'm in a couple of groups that are basically companies and I get all their status updates as well as the ability to turn on or off notifications for them (one I keep on because I really like the company).