Back then, we just had individual communities under their own web domains. That meant that you needed to have lurked on the site for a bit, understood the culture, and then make the decision to make an account and join the discussion.

Forums also had a unique look and feel, even if they were just different color themes selected from the admin panel.

With Reddit, you have individual communities, but one account gets you access to them all. So you will get people who joined a 'foreveralone' group and can now frictionlessly post on relationship subs about how women don't want nice guys like him, they want bad boys who'll abuse them.