I disagree. I think sub division is what makes sites grow. People get connected to a particular sub community and they go to that website to exclusively use that sub. If the sub isn't available then people aren't really interested in general conversation with thousands of topics mixed together. That's why reddit got so big. Probably half of the user base doesn't even know the rest of reddit exists. They just use it for information about magic cards or information about fermentation or discussion about a favorite TV show.